\[ %% % Add your macros here; they'll be included in pdf and html output. %% \newcommand{\R}{\mathbb{R}} % reals \newcommand{\E}{\mathbb{E}} % expectation \renewcommand{\P}{\mathbb{P}} % probability \DeclareMathOperator{\logit}{logit} \DeclareMathOperator{\logistic}{logistic} \DeclareMathOperator{\sd}{sd} \DeclareMathOperator{\var}{var} \DeclareMathOperator{\cov}{cov} \DeclareMathOperator{\Normal}{Normal} \DeclareMathOperator{\Poisson}{Poisson} \DeclareMathOperator{\Beta}{Beta} \DeclareMathOperator{\Binom}{Binomial} \DeclareMathOperator{\Gam}{Gamma} \DeclareMathOperator{\Exp}{Exponential} \DeclareMathOperator{\Cauchy}{Cauchy} \DeclareMathOperator{\Unif}{Unif} \DeclareMathOperator{\Dirichlet}{Dirichlet} \newcommand{\given}{\;\vert\;} \]

Poisson regression, sparsification, and model selection

Peter Ralph

29 January 2018 – Advanced Biological Statistics

Overview

Summary

So far we looked at fitting probabilities of binary events predicted by various sorts of explanatory variables - for instance, “logistic regression”.

Grouping means together using hyperpriors induced shrinkage, allowing sharing of information between groups.

Simulation is also useful for debugging and, vaguely, checking model fit.

Next up

Next we’ll hit many of the same topics in a slightly different context: when the data are counts rather than proportions. (“How many birds are there?” instead of “How many of the birds are red?”)

We’ll also see how to use simulation to do formal model comparisons.

Count data

A hypothetical situation:

  1. We have counts of transcript numbers,

  2. from some individuals of different ages and past exposures to solar irradiation,

  3. of two genotypes.

Model:

  • Counts are Poisson,

  • with mean that depends on age and exposure,

  • but effect of exposure depends on genotype.

  • But actually, counts are overdispersed, so make the means random, and lognormally distributed.
  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype.

  4. But actually, counts are overdispersed, so make the means random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \end{aligned}\]

  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype.

  4. But actually, counts are overdispersed, so make the means random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &= a + b \times \text{age}_i + c \times \text{exposure}_i \end{aligned}\]

  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype.

  4. But actually, counts are overdispersed, so make the means random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &= \exp\left( a_{g_i} + b \times \text{age}_i + c_{g_i} \times \text{exposure}_i \right) \end{aligned}\]

  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype.

  4. But actually, counts are overdispersed, so make the means random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &= \exp(W_i) \\ W_i &\sim \Normal(y_i, \sigma) \\ y_i &= a_{g_i} + b \times \text{age}_i + c_{g_i} \times \text{exposure}_i \end{aligned}\]

  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype.

  4. But actually, counts are overdispersed, so make the means random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &\sim \log\Normal(y_i, \sigma) \\ y_i &= a_{g_i} + b \times \text{age}_i + c_{g_i} \times \text{exposure}_i \end{aligned}\]

Simulate these and compare.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &= \exp\left(a_{g_i} + b \times \text{age}_i \right.\\ &\qquad \left. {} + c_{g_i} \times \text{exposure}_i \right) \end{aligned}\]

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &= \exp(X_i) \\ X_i &\sim \Normal(y_i, \sigma) \\ y_i &= a_{g_i} + b \times \text{age}_i \\ &\qquad {} + c_{g_i} \times \text{exposure}_i \end{aligned}\]

Simulate this.

Write a Stan block

  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype;

  4. means are random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &\sim \log\Normal(y_i, \sigma) \\ y_i &= a_{g_i} + b \times \text{age}_i \\ &\qquad {} + c_{g_i} \times \text{exposure}_i \end{aligned}\]

data {
    // what we know
}
parameters {
    // what we want to find out
}
model {
    // how they relate
}

The result

  1. Counts are Poisson,

  2. with mean that depends on age and exposure,

  3. but effect of exposure depends on genotype;

  4. means are random, and lognormally distributed.

\[\begin{aligned} Z_i &\sim \Poisson(\mu_i) \\ \mu_i &\sim \log\Normal(y_i, \sigma) \\ y_i &= a_{g_i} + b \times \text{age}_i \\ &\qquad {} + c_{g_i} \times \text{exposure}_i \end{aligned}\]

new_block <- "data {
    int N; // number of obs
    vector[N] age;
    int geno[N];
    vector[N] expo;
    int counts[N];
    int ngeno;
}
parameters {
    real<lower=0> mu[N]; // per-indiv 'mean'
    vector[ngeno] a;
    real b;
    vector[ngeno] c;
    real<lower=0> sigma;
}
model {
    vector[N] y;
    y = a[geno] + b * age + c[geno] .* expo;
    // for (i in 1:N) {
    //     y[i] = a[geno[i]] + b * age[i] + c[geno[i]] * expo[i];
    // }
    counts ~ poisson(mu);
    mu ~ lognormal(y, sigma);
    a ~ normal(0, 10);
    b ~ normal(0, 10);
    c ~ normal(0, 10);
    sigma ~ normal(0, 10);
}"

data_list <- list(
            N = nrow(data),
            age = data$age,
            geno = data$genotype,
            expo = data$exposure,
            counts = data$counts,
            ngeno = length(unique(data$genotype)))



new_fit <- stan(model_code=new_block, 
             data=data_list,
             control=list(max_treedepth=12),
             iter=100, chains=3)

Stochastic minute

The Poisson distribution

If \(N \sim \Poisson(\mu)\) then \(N \ge 0\) and \[\begin{aligned} \P\{N = k\} = \frac{\mu^k}{k!} e^{-\mu} \end{aligned}\]

  • \(N\) is a nonnegative integer (i.e., a count)

  • \(\E[N] = \var[N] = \mu\)

  • If a machine makes widgets very fast, producing on average one broken widget per minute (and many good ones), each breaking independent of the others, then the number of broken widgets in \(\mu\) minutes is \(\Poisson(\mu)\).

  • If busses arrive randomly every \(\Exp(1)\) minutes, then the number of busses to arrive in \(\mu\) minutes is \(\Poisson(\mu)\).

Two models

Step back: a simple model

Note: scaling the data helps Stan find the right scale to move on.

## Inference for Stan model: e04ed23635a1fc5cf9233f0866bdf5cf.
## 3 chains, each with iter=1000; warmup=500; thin=1; 
## post-warmup draws per chain=500, total post-warmup draws=1500.
## 
##          mean se_mean   sd     2.5%      25%      50%      75%    97.5%
## a[1]     2.24    0.00 0.02     2.20     2.22     2.24     2.25     2.28
## a[2]     1.58    0.00 0.03     1.53     1.56     1.58     1.60     1.64
## b        0.91    0.00 0.01     0.89     0.90     0.91     0.92     0.93
## c[1]     0.13    0.00 0.01     0.10     0.12     0.13     0.14     0.16
## c[2]    -0.38    0.00 0.03    -0.44    -0.40    -0.38    -0.36    -0.32
## lp__ 13445.48    0.08 1.67 13441.29 13444.65 13445.85 13446.71 13447.62
##      n_eff Rhat
## a[1]  1079    1
## a[2]  1260    1
## b     1298    1
## c[1]  1500    1
## c[2]  1500    1
## lp__   489    1
## 
## Samples were drawn using NUTS(diag_e) at Mon Jan 29 22:36:19 2018.
## For each parameter, n_eff is a crude measure of effective sample size,
## and Rhat is the potential scale reduction factor on split chains (at 
## convergence, Rhat=1).

Aside: what happens during “warmup”?

plot of chunk the_warmup

The usual plot (without warmup)

plot of chunk not_warmup

How’d we do?

Here are posterior distributions of the parameters, with the true values in red. plot of chunk true_fit_1

What happened?

Goodness of fit

Let’s simulate up data under this model to check for goodness of fit.

We expect to not see a good fit. (Why?)

100 datasets from the posterior distribution

The true data are overdispersed relative to our simulations

plot of chunk plot_post_sims1

Including overdispersion

A random mean adds a level of randomness

## Inference for Stan model: cc2fed94df9d2f003676a260a7adbf8e.
## 3 chains, each with iter=1000; warmup=500; thin=1; 
## post-warmup draws per chain=500, total post-warmup draws=1500.
## 
##             mean se_mean    sd     2.5%      25%      50%      75%
## a[1]        1.45    0.00  0.08     1.29     1.39     1.44     1.50
## a[2]        1.27    0.00  0.08     1.12     1.22     1.27     1.33
## b           0.91    0.00  0.05     0.81     0.87     0.91     0.94
## c[1]        0.13    0.00  0.07    -0.01     0.08     0.12     0.17
## c[2]       -0.40    0.00  0.09    -0.58    -0.46    -0.40    -0.33
## mu[1]       3.81    0.04  1.68     1.23     2.60     3.58     4.70
## mu[2]       3.00    0.04  1.62     0.82     1.84     2.68     3.80
## mu[3]       5.43    0.06  2.20     1.97     3.89     5.14     6.67
## mu[4]      12.72    0.09  3.43     6.82    10.32    12.43    14.77
## mu[5]       1.90    0.03  1.13     0.43     1.09     1.64     2.44
## mu[6]      45.07    0.17  6.69    33.06    40.68    44.60    49.57
## mu[7]       3.90    0.05  1.92     1.30     2.51     3.55     4.90
## mu[8]       1.12    0.02  0.78     0.20     0.55     0.93     1.46
## mu[9]       2.55    0.03  1.32     0.72     1.60     2.29     3.25
## mu[10]     20.51    0.11  4.39    12.82    17.31    20.30    23.26
## mu[11]      0.66    0.01  0.56     0.08     0.29     0.51     0.83
## mu[12]      0.64    0.01  0.54     0.08     0.26     0.49     0.84
## mu[13]      1.44    0.02  0.95     0.29     0.76     1.22     1.88
## mu[14]      2.03    0.03  1.18     0.48     1.18     1.76     2.62
## mu[15]     16.23    0.10  3.94     9.33    13.46    15.82    18.82
## mu[16]    642.68    0.66 25.72   595.43   625.25   641.75   659.83
## mu[17]      1.30    0.02  0.86     0.23     0.69     1.09     1.68
## mu[18]      1.48    0.02  0.94     0.31     0.80     1.27     1.96
## mu[19]      6.30    0.06  2.34     2.48     4.66     6.04     7.59
## mu[20]      1.86    0.03  1.15     0.38     1.01     1.62     2.45
## mu[21]      5.58    0.06  2.23     2.20     3.91     5.24     7.00
## mu[22]      3.11    0.04  1.52     0.96     2.03     2.84     3.95
## mu[23]      3.15    0.04  1.51     0.93     2.02     2.91     4.06
## mu[24]     38.38    0.16  6.22    27.45    33.92    37.99    42.45
## mu[25]      2.46    0.04  1.41     0.61     1.46     2.17     3.10
## mu[26]      1.32    0.02  0.90     0.25     0.68     1.10     1.76
## mu[27]      5.05    0.06  2.14     1.87     3.43     4.71     6.31
## mu[28]      4.29    0.05  1.95     1.37     2.90     4.01     5.27
## mu[29]      3.14    0.04  1.59     0.94     1.91     2.85     4.07
## mu[30]      3.40    0.04  1.65     1.09     2.20     3.09     4.20
## mu[31]      2.57    0.04  1.42     0.65     1.55     2.31     3.24
## mu[32]      1.04    0.02  0.74     0.17     0.52     0.85     1.37
## mu[33]      3.76    0.05  1.79     1.13     2.49     3.46     4.76
## mu[34]      1.17    0.02  0.79     0.22     0.58     0.99     1.51
## mu[35]      2.38    0.03  1.29     0.64     1.47     2.10     3.02
## mu[36]      2.06    0.03  1.17     0.50     1.21     1.84     2.65
## mu[37]      3.94    0.05  1.88     1.25     2.55     3.69     4.94
## mu[38]      1.75    0.03  1.07     0.38     0.97     1.52     2.29
## mu[39]      1.58    0.03  1.04     0.32     0.84     1.33     2.00
## mu[40]      1.48    0.02  0.97     0.28     0.81     1.27     1.92
## mu[41]      4.54    0.05  1.85     1.69     3.23     4.31     5.57
## mu[42]      5.58    0.05  2.12     2.33     4.03     5.25     6.84
## mu[43]     10.14    0.08  3.13     4.80     7.99     9.81    11.90
## mu[44]     21.70    0.12  4.52    13.73    18.39    21.38    24.66
## mu[45]      1.18    0.02  0.86     0.20     0.59     0.98     1.50
## mu[46]      1.08    0.02  0.74     0.17     0.55     0.90     1.41
## mu[47]      5.56    0.06  2.19     2.18     3.98     5.26     6.86
## mu[48]      4.21    0.05  1.78     1.53     2.95     3.97     5.20
## mu[49]      1.87    0.03  1.11     0.44     1.09     1.60     2.39
## mu[50]      9.36    0.08  2.95     4.74     7.23     8.99    11.09
## mu[51]     47.43    0.18  6.82    35.90    42.50    46.94    51.65
## mu[52]      1.43    0.02  0.95     0.30     0.72     1.19     1.88
## mu[53]      5.35    0.05  2.13     2.07     3.80     5.10     6.51
## mu[54]     33.75    0.14  5.39    24.30    29.81    33.58    37.25
## mu[55]     23.93    0.12  4.79    15.15    20.63    23.69    27.00
## mu[56]     84.01    0.22  8.49    68.44    78.25    83.75    89.33
## mu[57]     12.09    0.09  3.47     6.16     9.61    11.75    14.17
## mu[58]      1.49    0.03  0.97     0.28     0.81     1.27     1.94
## mu[59]      4.10    0.04  1.74     1.55     2.81     3.80     5.10
## mu[60]      0.91    0.02  0.71     0.15     0.42     0.70     1.20
## mu[61]     11.78    0.09  3.38     6.10     9.27    11.59    13.70
## mu[62]      3.41    0.04  1.64     1.05     2.22     3.15     4.27
## mu[63]      0.47    0.01  0.42     0.05     0.18     0.34     0.63
## mu[64]      1.18    0.02  0.84     0.21     0.61     0.97     1.52
## mu[65]     12.65    0.09  3.35     6.96    10.22    12.39    14.67
## mu[66]      1.21    0.02  0.81     0.22     0.64     1.02     1.63
## mu[67]     17.26    0.10  3.98    10.15    14.28    17.06    19.84
## mu[68]      2.10    0.03  1.29     0.48     1.18     1.83     2.71
## mu[69]      1.78    0.03  1.13     0.35     0.98     1.50     2.30
## mu[70]      1.48    0.03  1.00     0.29     0.77     1.24     1.95
## mu[71]      1.85    0.03  1.10     0.43     1.04     1.62     2.37
## mu[72]     46.88    0.17  6.72    35.04    42.11    46.37    51.23
## mu[73]      1.53    0.03  1.05     0.28     0.80     1.29     1.98
## mu[74]      2.84    0.04  1.53     0.66     1.72     2.58     3.66
## mu[75]     14.41    0.10  3.71     8.07    11.76    13.99    16.66
## mu[76]      3.74    0.05  1.74     1.24     2.48     3.39     4.72
## mu[77]     32.16    0.14  5.61    22.13    28.34    31.92    35.72
## mu[78]     11.76    0.09  3.31     6.24     9.32    11.47    13.64
## mu[79]      9.13    0.07  2.81     4.42     7.10     8.90    10.86
## mu[80]      1.74    0.03  1.10     0.39     0.97     1.52     2.24
## mu[81]      6.71    0.07  2.54     2.80     4.91     6.34     8.10
## mu[82]      1.85    0.03  1.08     0.42     1.07     1.63     2.34
## mu[83]      2.14    0.03  1.24     0.51     1.27     1.89     2.73
## mu[84]      6.78    0.06  2.50     2.86     4.94     6.51     8.32
## mu[85]      3.28    0.04  1.58     1.05     2.18     3.05     4.07
## mu[86]     18.33    0.11  4.29    11.11    15.21    17.93    21.02
## mu[87]     11.32    0.08  3.23     5.86     9.04    11.01    13.42
## mu[88]      3.31    0.04  1.72     0.97     2.05     2.96     4.24
## mu[89]     21.93    0.11  4.44    14.29    18.79    21.65    24.84
## mu[90]      4.09    0.05  1.90     1.38     2.68     3.75     5.10
## mu[91]      4.49    0.05  2.06     1.53     2.98     4.11     5.57
## mu[92]      5.46    0.06  2.23     2.02     3.87     5.11     6.77
## mu[93]      2.70    0.04  1.41     0.76     1.66     2.45     3.47
## mu[94]     21.54    0.12  4.48    13.63    18.29    21.26    24.33
## mu[95]      1.35    0.02  0.90     0.24     0.69     1.13     1.76
## mu[96]    195.76    0.37 14.19   169.01   186.34   195.35   204.67
## mu[97]      3.88    0.05  1.79     1.31     2.59     3.57     4.93
## mu[98]      3.16    0.04  1.60     0.88     1.99     2.89     4.00
## mu[99]      4.37    0.05  1.93     1.52     2.92     4.06     5.56
## mu[100]     0.74    0.02  0.63     0.11     0.32     0.57     0.99
## mu[101]     6.21    0.06  2.17     2.78     4.60     6.01     7.63
## mu[102]    13.58    0.10  3.81     7.13    10.90    13.22    15.79
## mu[103]     2.85    0.04  1.47     0.88     1.74     2.57     3.61
## mu[104]    29.54    0.14  5.42    20.18    25.86    29.30    32.91
## mu[105]     3.18    0.04  1.65     0.86     2.03     2.88     4.02
## mu[106]     2.01    0.03  1.23     0.43     1.12     1.75     2.59
## mu[107]    15.69    0.10  3.72     9.26    13.09    15.38    18.04
## mu[108]     1.75    0.03  1.13     0.34     0.93     1.48     2.30
## mu[109]    39.67    0.16  6.16    28.33    35.44    39.34    43.55
## mu[110]     1.70    0.03  1.11     0.34     0.91     1.44     2.24
## mu[111]     4.90    0.05  2.12     1.76     3.33     4.59     6.05
## mu[112]     4.97    0.05  1.99     1.92     3.56     4.69     6.07
## mu[113]     0.67    0.01  0.56     0.08     0.28     0.51     0.86
## mu[114]     4.24    0.05  1.96     1.43     2.79     3.92     5.35
## mu[115]    54.60    0.18  7.06    42.21    49.38    54.24    59.23
## mu[116]     2.75    0.04  1.40     0.74     1.71     2.51     3.54
## mu[117]     1.06    0.02  0.77     0.20     0.52     0.88     1.36
## mu[118]    13.82    0.10  3.73     7.52    11.06    13.53    16.16
## mu[119]     1.96    0.03  1.09     0.45     1.16     1.75     2.49
## mu[120]     2.00    0.03  1.25     0.44     1.15     1.71     2.54
## mu[121]     2.98    0.04  1.50     0.87     1.85     2.71     3.79
## mu[122]     1.27    0.02  0.95     0.21     0.60     1.02     1.68
## mu[123]     4.52    0.05  1.93     1.63     3.13     4.22     5.55
## mu[124]     2.43    0.04  1.38     0.56     1.47     2.15     3.06
## mu[125]    34.55    0.15  5.76    24.17    30.52    34.20    38.27
## mu[126]     1.35    0.02  0.93     0.26     0.69     1.15     1.76
## mu[127]     3.60    0.04  1.72     1.12     2.34     3.26     4.50
## mu[128]     7.41    0.07  2.53     3.34     5.68     7.07     8.82
## mu[129]     7.08    0.06  2.48     3.19     5.27     6.81     8.57
## mu[130]     3.23    0.04  1.60     0.94     2.02     2.94     4.11
## mu[131]    86.62    0.23  8.98    70.42    80.06    86.25    92.60
## mu[132]    11.36    0.09  3.35     5.74     8.95    11.04    13.51
## mu[133]     1.44    0.03  0.99     0.25     0.75     1.18     1.87
## mu[134]    18.26    0.11  4.18    11.14    15.32    17.95    20.85
## mu[135]    10.76    0.08  3.16     5.54     8.54    10.41    12.70
## mu[136]     2.60    0.04  1.41     0.67     1.56     2.35     3.35
## mu[137]     7.95    0.07  2.67     3.80     5.93     7.54     9.74
## mu[138]     0.87    0.02  0.70     0.11     0.39     0.68     1.15
## mu[139]     4.85    0.05  2.03     1.73     3.36     4.53     5.98
## mu[140]     3.94    0.05  1.76     1.43     2.63     3.66     4.93
## mu[141]     0.72    0.02  0.58     0.10     0.33     0.57     0.96
## mu[142]     3.95    0.05  1.85     1.27     2.59     3.66     4.97
## mu[143]     2.99    0.04  1.44     0.89     1.94     2.74     3.73
## mu[144]     0.70    0.01  0.55     0.09     0.31     0.55     0.93
## mu[145]     1.56    0.03  1.06     0.26     0.85     1.32     2.00
## mu[146]     0.98    0.02  0.76     0.15     0.45     0.78     1.28
## mu[147]     8.87    0.07  2.79     4.36     6.79     8.55    10.60
## mu[148]    17.23    0.11  4.14    10.06    14.37    16.94    19.73
## mu[149]    23.08    0.12  4.65    15.19    19.57    22.77    26.09
## mu[150]    31.48    0.14  5.42    21.83    27.54    31.15    34.84
## mu[151]     1.22    0.02  0.88     0.19     0.56     0.99     1.58
## mu[152]     0.87    0.02  0.67     0.13     0.40     0.68     1.12
## mu[153]     1.75    0.03  1.10     0.35     0.96     1.51     2.29
## mu[154]    59.18    0.19  7.54    44.86    53.97    59.08    63.71
## mu[155]     1.59    0.03  1.01     0.33     0.83     1.36     2.08
## mu[156]     1.23    0.02  0.82     0.24     0.64     1.02     1.60
## mu[157]    10.65    0.08  3.10     5.33     8.59    10.37    12.44
## mu[158]     0.89    0.02  0.75     0.13     0.40     0.67     1.13
## mu[159]    11.85    0.09  3.39     6.28     9.33    11.58    13.97
## mu[160]     3.19    0.04  1.54     0.96     2.01     2.92     4.02
## mu[161]    19.71    0.11  4.17    12.45    16.80    19.39    22.23
## mu[162]     1.97    0.03  1.15     0.41     1.13     1.73     2.56
## mu[163]     4.92    0.05  2.03     1.85     3.50     4.61     6.04
## mu[164]     1.86    0.03  1.14     0.40     1.04     1.61     2.40
## mu[165]     1.29    0.02  0.91     0.22     0.66     1.07     1.66
## mu[166]     1.59    0.03  1.02     0.34     0.86     1.36     2.10
## mu[167]    16.15    0.10  3.89     9.46    13.46    15.96    18.55
## mu[168]     3.65    0.04  1.67     1.18     2.48     3.38     4.50
## mu[169]     2.16    0.03  1.18     0.60     1.28     1.93     2.75
## mu[170]    49.22    0.18  7.09    35.90    44.43    48.95    53.40
## mu[171]     2.95    0.04  1.48     0.87     1.89     2.68     3.69
## mu[172]     1.31    0.02  0.92     0.23     0.65     1.09     1.72
## mu[173]     8.92    0.07  2.86     4.22     6.85     8.60    10.72
## mu[174]    29.94    0.14  5.43    20.39    26.04    29.57    33.60
## mu[175]    12.17    0.09  3.32     6.67     9.80    11.80    14.15
## mu[176]    28.93    0.14  5.34    19.85    25.13    28.56    32.35
## mu[177]     0.95    0.02  0.73     0.15     0.44     0.75     1.29
## mu[178]     1.06    0.02  0.79     0.16     0.50     0.86     1.42
## mu[179]     1.50    0.02  0.94     0.30     0.79     1.28     1.99
## mu[180]     0.48    0.01  0.43     0.05     0.19     0.35     0.64
## mu[181]     8.90    0.07  2.86     4.18     6.94     8.50    10.60
## mu[182]     2.07    0.03  1.25     0.45     1.17     1.81     2.67
## mu[183]     1.56    0.03  1.02     0.31     0.82     1.33     1.98
## mu[184]    14.28    0.09  3.64     8.37    11.76    13.92    16.53
## mu[185]     3.16    0.04  1.56     0.86     2.01     2.93     4.02
## mu[186]     4.83    0.05  2.08     1.84     3.28     4.46     6.03
## mu[187]     1.46    0.03  1.04     0.23     0.76     1.21     1.87
## mu[188]   121.93    0.29 11.12   101.37   114.00   121.31   129.74
## mu[189]     6.03    0.06  2.31     2.50     4.34     5.68     7.42
## mu[190]    18.66    0.11  4.33    11.29    15.71    18.23    21.27
## mu[191]     1.91    0.03  1.17     0.42     1.06     1.66     2.46
## mu[192]    18.60    0.11  4.12    11.41    15.70    18.28    21.20
## mu[193]     2.52    0.04  1.37     0.69     1.52     2.25     3.26
## mu[194]     1.63    0.03  1.01     0.35     0.90     1.39     2.15
## mu[195]     0.69    0.01  0.57     0.10     0.30     0.53     0.90
## mu[196]     3.21    0.04  1.65     1.02     1.96     2.89     4.11
## mu[197]    66.11    0.21  8.33    50.09    60.41    65.75    71.30
## mu[198]     3.24    0.04  1.59     0.99     2.07     2.98     4.09
## mu[199]     4.09    0.05  1.83     1.35     2.74     3.83     5.12
## mu[200]     1.77    0.03  1.08     0.38     0.99     1.55     2.28
## mu[201]     6.98    0.07  2.54     2.95     5.11     6.61     8.70
## mu[202]     3.61    0.04  1.68     1.15     2.39     3.33     4.50
## mu[203]     1.56    0.03  0.99     0.31     0.81     1.35     2.05
## mu[204]     3.65    0.04  1.66     1.22     2.46     3.40     4.52
## mu[205]     7.43    0.07  2.61     3.22     5.51     7.22     8.93
## mu[206]     1.06    0.02  0.74     0.18     0.54     0.87     1.35
## mu[207]    38.37    0.16  6.13    27.09    34.20    38.04    42.18
## mu[208]     1.64    0.03  1.04     0.35     0.89     1.41     2.13
## mu[209]     2.66    0.04  1.40     0.72     1.67     2.40     3.36
## mu[210]     1.29    0.02  0.93     0.22     0.64     1.06     1.66
## mu[211]     9.20    0.07  2.87     4.54     7.07     8.88    10.96
## mu[212]     5.00    0.05  2.08     1.92     3.53     4.66     6.20
## mu[213]    16.16    0.10  3.89     9.40    13.44    15.93    18.45
## mu[214]     2.85    0.04  1.43     0.86     1.79     2.58     3.65
## mu[215]     0.82    0.02  0.67     0.12     0.36     0.64     1.10
## mu[216]     1.92    0.03  1.19     0.39     1.07     1.62     2.47
## mu[217]    88.94    0.24  9.31    72.02    82.49    88.66    94.98
## mu[218]     3.49    0.04  1.70     1.02     2.27     3.23     4.37
## mu[219]     2.16    0.03  1.20     0.54     1.28     1.92     2.79
## mu[220]     1.05    0.02  0.75     0.18     0.51     0.86     1.37
## mu[221]     2.52    0.04  1.44     0.65     1.49     2.24     3.19
## mu[222]    10.49    0.08  3.20     5.35     8.14    10.08    12.60
## mu[223]     1.56    0.03  0.99     0.29     0.86     1.32     1.99
## mu[224]     5.54    0.06  2.15     2.15     4.01     5.24     6.79
## mu[225]     5.88    0.06  2.30     2.25     4.23     5.57     7.28
## mu[226]     1.18    0.02  0.83     0.20     0.57     0.98     1.54
## mu[227]    26.85    0.12  4.80    18.05    23.52    26.55    29.91
## mu[228]    16.14    0.10  3.84     9.44    13.36    15.92    18.38
## mu[229]    73.98    0.24  9.13    56.73    67.83    73.54    79.87
## mu[230]     1.16    0.02  0.78     0.21     0.62     0.97     1.50
## mu[231]     4.32    0.05  1.85     1.53     2.95     4.02     5.45
## mu[232]    19.25    0.11  4.36    11.82    16.15    18.98    22.15
## mu[233]    37.84    0.16  6.36    26.71    33.35    37.31    41.89
## mu[234]    13.41    0.09  3.60     7.34    10.84    12.97    15.52
## mu[235]     4.06    0.04  1.72     1.55     2.79     3.80     5.04
## mu[236]     2.37    0.03  1.32     0.62     1.42     2.09     3.04
## mu[237]     1.44    0.02  0.95     0.30     0.76     1.22     1.88
## mu[238]     1.56    0.03  1.04     0.27     0.82     1.31     2.03
## mu[239]     4.95    0.06  2.18     1.70     3.36     4.62     6.10
## mu[240]     9.91    0.08  3.19     4.74     7.64     9.61    11.78
## mu[241]     5.15    0.05  2.12     1.97     3.59     4.88     6.41
## mu[242]    11.74    0.09  3.31     6.35     9.38    11.37    13.69
## mu[243]     4.50    0.05  2.03     1.39     3.10     4.19     5.58
## mu[244]     4.12    0.05  1.84     1.43     2.81     3.82     5.06
## mu[245]    16.08    0.10  3.88     9.48    13.31    15.67    18.57
## mu[246]     4.43    0.05  1.90     1.59     3.03     4.16     5.57
## mu[247]     2.05    0.03  1.25     0.46     1.16     1.77     2.61
## mu[248]     0.59    0.01  0.52     0.06     0.23     0.43     0.77
## mu[249]     4.43    0.05  2.01     1.51     2.96     4.15     5.55
## mu[250]     2.18    0.03  1.22     0.58     1.31     1.94     2.83
## mu[251]     3.56    0.04  1.64     1.21     2.39     3.24     4.49
## mu[252]     9.32    0.07  2.82     4.76     7.28     9.09    10.89
## mu[253]     8.27    0.07  2.75     3.84     6.25     7.98     9.94
## mu[254]     7.76    0.07  2.69     3.49     5.74     7.48     9.49
## mu[255]     3.33    0.04  1.60     1.06     2.14     3.03     4.26
## mu[256]     1.37    0.02  0.91     0.25     0.71     1.15     1.77
## mu[257]     8.44    0.07  2.62     4.21     6.62     8.16     9.83
## mu[258]     0.63    0.01  0.54     0.08     0.26     0.47     0.81
## mu[259]     1.99    0.03  1.17     0.50     1.11     1.71     2.60
## mu[260]     1.40    0.03  0.98     0.25     0.73     1.17     1.78
## mu[261]     0.77    0.02  0.60     0.11     0.35     0.60     1.04
## mu[262]     1.96    0.03  1.19     0.42     1.05     1.70     2.61
## mu[263]     3.47    0.04  1.58     1.12     2.30     3.23     4.43
## mu[264]     1.55    0.03  1.00     0.29     0.84     1.33     2.05
## mu[265]     6.40    0.06  2.33     2.60     4.75     6.12     7.70
## mu[266]     6.50    0.06  2.48     2.76     4.61     6.21     8.09
## mu[267]    79.08    0.24  9.22    61.68    72.76    78.78    85.14
## mu[268]     5.45    0.06  2.16     2.27     3.87     5.15     6.76
## mu[269]     0.88    0.02  0.67     0.14     0.40     0.69     1.16
## mu[270]     1.92    0.03  1.17     0.44     1.09     1.67     2.45
## mu[271]     3.93    0.05  1.78     1.39     2.61     3.68     4.88
## mu[272]    16.80    0.10  4.05     9.91    13.75    16.55    19.43
## mu[273]     1.08    0.02  0.83     0.16     0.48     0.84     1.39
## mu[274]     4.34    0.05  1.83     1.53     2.99     4.10     5.42
## mu[275]     0.82    0.02  0.65     0.11     0.35     0.64     1.08
## mu[276]     3.40    0.04  1.63     1.04     2.19     3.14     4.33
## mu[277]     1.14    0.02  0.83     0.18     0.56     0.93     1.49
## mu[278]     2.76    0.04  1.41     0.83     1.72     2.47     3.55
## mu[279]     3.50    0.04  1.71     1.13     2.33     3.19     4.40
## mu[280]     5.25    0.05  2.07     2.11     3.81     4.97     6.36
## mu[281]     0.81    0.02  0.70     0.11     0.33     0.61     1.06
## mu[282]     4.94    0.05  1.99     1.88     3.47     4.64     6.16
## mu[283]     4.76    0.05  2.02     1.71     3.26     4.47     6.02
## mu[284]     1.26    0.02  0.92     0.19     0.63     1.02     1.64
## mu[285]     6.34    0.06  2.41     2.59     4.59     6.03     7.73
## mu[286]     3.66    0.04  1.74     1.18     2.36     3.36     4.70
## mu[287]     3.43    0.04  1.67     1.06     2.21     3.08     4.34
## mu[288]    15.30    0.10  3.93     8.74    12.53    14.92    17.62
## mu[289]    15.54    0.10  3.90     8.88    12.86    15.19    17.92
## mu[290]     6.15    0.06  2.29     2.52     4.54     5.89     7.49
## mu[291]     3.00    0.04  1.52     0.89     1.87     2.73     3.81
## mu[292]     3.60    0.04  1.55     1.30     2.48     3.39     4.45
## mu[293]     2.67    0.04  1.44     0.74     1.61     2.37     3.49
## mu[294]    86.55    0.24  9.31    70.55    79.83    86.02    92.46
## mu[295]    16.12    0.10  3.98     9.24    13.18    15.76    18.67
## mu[296]     2.02    0.03  1.15     0.52     1.17     1.78     2.63
## mu[297]     4.82    0.05  2.09     1.74     3.31     4.56     5.91
## mu[298]     1.82    0.03  1.16     0.35     1.01     1.56     2.34
## mu[299]    65.25    0.20  7.89    50.31    59.89    64.99    70.29
## mu[300]     1.62    0.03  1.03     0.32     0.90     1.40     2.09
## mu[301]     1.98    0.03  1.23     0.44     1.09     1.71     2.59
## mu[302]     5.31    0.06  2.35     1.75     3.64     4.89     6.74
## mu[303]     1.78    0.03  1.11     0.37     0.97     1.53     2.31
## mu[304]     1.92    0.03  1.16     0.40     1.06     1.68     2.53
## mu[305]     0.96    0.02  0.74     0.14     0.45     0.76     1.31
## mu[306]    15.69    0.10  3.82     9.06    13.12    15.43    17.94
## mu[307]     1.13    0.02  0.74     0.20     0.60     0.96     1.49
## mu[308]     5.95    0.06  2.19     2.45     4.37     5.71     7.14
## mu[309]    66.51    0.21  8.11    51.34    60.90    65.86    71.96
## mu[310]     2.35    0.03  1.32     0.59     1.38     2.12     3.00
## mu[311]    11.16    0.09  3.30     5.70     8.78    10.83    13.16
## mu[312]     1.88    0.03  1.14     0.39     1.04     1.63     2.44
## mu[313]    36.87    0.16  6.21    26.09    32.47    36.34    40.63
## mu[314]    11.64    0.09  3.33     6.15     9.21    11.28    13.60
## mu[315]     5.14    0.06  2.14     1.90     3.60     4.86     6.35
## mu[316]     2.82    0.04  1.40     0.85     1.85     2.57     3.53
## mu[317]   259.16    0.42 16.16   228.05   248.29   259.13   269.73
## mu[318]     4.96    0.05  2.08     1.78     3.36     4.67     6.20
## mu[319]     1.64    0.03  1.00     0.35     0.92     1.41     2.13
## mu[320]     1.81    0.03  1.08     0.38     1.03     1.60     2.33
## mu[321]     1.83    0.03  1.07     0.45     1.06     1.61     2.35
## mu[322]     1.13    0.02  0.89     0.16     0.49     0.90     1.46
## mu[323]     6.54    0.06  2.16     2.95     4.93     6.32     7.93
## mu[324]     4.39    0.05  2.04     1.49     2.92     4.05     5.49
## mu[325]     3.76    0.04  1.71     1.27     2.45     3.45     4.83
## mu[326]    26.79    0.13  5.11    17.43    23.26    26.52    29.98
## mu[327]     3.74    0.05  1.80     1.11     2.47     3.44     4.72
## mu[328]     1.05    0.02  0.81     0.14     0.50     0.82     1.36
## mu[329]     1.43    0.03  1.00     0.25     0.72     1.17     1.91
## mu[330]     3.29    0.04  1.60     0.93     2.17     3.00     4.15
## mu[331]     2.97    0.04  1.57     0.80     1.87     2.66     3.79
## mu[332]    13.30    0.09  3.47     7.39    10.74    13.02    15.47
## mu[333]    55.20    0.19  7.29    41.79    50.36    54.94    60.14
## mu[334]     1.95    0.03  1.14     0.44     1.14     1.70     2.50
## mu[335]    79.89    0.22  8.53    64.32    73.77    79.65    85.67
## mu[336]     1.96    0.03  1.16     0.45     1.14     1.71     2.51
## mu[337]     4.12    0.05  1.97     1.32     2.67     3.79     5.20
## mu[338]     1.52    0.03  0.99     0.32     0.85     1.29     1.92
## mu[339]     2.73    0.04  1.51     0.69     1.62     2.43     3.46
## mu[340]     1.86    0.03  1.10     0.44     1.05     1.60     2.43
## mu[341]     7.97    0.07  2.68     3.71     6.10     7.65     9.53
## mu[342]     5.04    0.05  2.12     1.77     3.44     4.80     6.29
## mu[343]     2.98    0.04  1.60     0.79     1.82     2.63     3.78
## mu[344]     1.87    0.03  1.14     0.41     1.05     1.63     2.41
## mu[345]     3.43    0.04  1.67     0.98     2.27     3.10     4.28
## mu[346]    14.10    0.09  3.63     8.01    11.49    13.82    16.24
## mu[347]     1.62    0.03  1.04     0.35     0.90     1.35     2.09
## mu[348]     4.27    0.05  1.93     1.44     2.87     3.98     5.31
## mu[349]     7.90    0.07  2.67     3.48     6.02     7.61     9.42
## mu[350]     2.61    0.04  1.41     0.74     1.62     2.34     3.31
## mu[351]     1.32    0.02  0.93     0.23     0.64     1.07     1.72
## mu[352]     6.96    0.06  2.47     2.94     5.20     6.71     8.32
## mu[353]     5.57    0.06  2.16     2.23     3.97     5.29     6.93
## mu[354]     1.40    0.02  0.93     0.25     0.73     1.18     1.83
## mu[355]    20.94    0.12  4.67    13.03    17.64    20.58    23.84
## mu[356]     5.03    0.05  2.06     1.99     3.54     4.70     6.25
## mu[357]     3.46    0.04  1.66     1.01     2.27     3.16     4.35
## mu[358]     1.13    0.02  0.78     0.22     0.57     0.93     1.49
## mu[359]     3.58    0.04  1.68     1.14     2.33     3.30     4.49
## mu[360]     0.76    0.02  0.58     0.13     0.35     0.61     1.00
## mu[361]     2.78    0.04  1.44     0.81     1.71     2.49     3.48
## mu[362]     1.35    0.02  0.92     0.26     0.69     1.13     1.72
## mu[363]     4.02    0.05  1.81     1.38     2.69     3.76     5.01
## mu[364]     4.95    0.05  1.98     1.85     3.53     4.66     6.06
## mu[365]     3.83    0.05  1.78     1.21     2.54     3.52     4.82
## mu[366]     3.12    0.04  1.57     0.93     1.95     2.81     3.99
## mu[367]    46.06    0.17  6.39    34.50    41.68    45.82    49.85
## mu[368]     1.36    0.02  0.87     0.31     0.72     1.15     1.77
## mu[369]     0.88    0.02  0.73     0.13     0.40     0.67     1.13
## mu[370]     0.95    0.02  0.73     0.14     0.45     0.75     1.23
## mu[371]     8.31    0.07  2.83     3.91     6.19     7.99    10.01
## mu[372]     1.13    0.02  0.83     0.15     0.54     0.90     1.46
## mu[373]    14.00    0.10  3.78     7.60    11.29    13.58    16.43
## mu[374]    60.14    0.20  7.77    45.93    55.05    59.89    65.13
## mu[375]     1.62    0.03  1.02     0.33     0.90     1.40     2.12
## mu[376]     3.90    0.05  1.79     1.31     2.58     3.61     4.89
## mu[377]     3.40    0.04  1.60     1.12     2.20     3.07     4.32
## mu[378]    19.92    0.12  4.53    12.28    16.75    19.57    22.73
## mu[379]    19.25    0.11  4.27    12.19    16.12    19.01    21.90
## mu[380]     0.75    0.02  0.64     0.09     0.31     0.58     0.99
## mu[381]     3.12    0.04  1.59     0.87     1.93     2.85     3.94
## mu[382]     2.54    0.04  1.43     0.63     1.53     2.23     3.31
## mu[383]    13.18    0.09  3.61     7.20    10.59    12.82    15.53
## mu[384]     3.30    0.04  1.66     0.95     2.10     2.99     4.22
## mu[385]    21.39    0.12  4.61    13.48    18.16    21.03    24.21
## mu[386]    11.42    0.08  3.11     6.28     9.16    11.08    13.26
## mu[387]   198.27    0.35 13.72   172.32   188.61   197.41   207.50
## mu[388]    13.20    0.09  3.39     7.31    10.85    13.02    15.26
## mu[389]     5.84    0.06  2.24     2.29     4.19     5.55     7.14
## mu[390]    40.71    0.16  6.26    29.33    36.54    40.29    44.79
## mu[391]    15.02    0.10  3.70     8.61    12.25    14.68    17.44
## mu[392]     6.09    0.06  2.22     2.69     4.43     5.81     7.43
## mu[393]     7.10    0.06  2.47     3.30     5.30     6.77     8.53
## mu[394]     1.24    0.02  0.81     0.25     0.64     1.04     1.63
## mu[395]    17.08    0.11  4.19    10.19    14.30    16.64    19.57
## mu[396]     8.08    0.06  2.51     4.06     6.22     7.80     9.60
## mu[397]     9.59    0.08  3.03     4.60     7.35     9.28    11.33
## mu[398]     3.22    0.04  1.65     0.88     1.99     2.96     4.15
## mu[399]     2.20    0.03  1.36     0.49     1.19     1.86     2.84
## mu[400]     5.28    0.05  2.11     2.01     3.73     4.92     6.52
## mu[401]     8.79    0.08  3.09     3.95     6.48     8.42    10.57
## mu[402]     1.00    0.02  0.74     0.16     0.48     0.80     1.31
## mu[403]     9.45    0.08  2.98     4.58     7.33     9.07    11.21
## mu[404]     1.58    0.03  0.99     0.34     0.86     1.36     2.07
## mu[405]    62.10    0.21  7.95    47.35    56.69    61.65    67.09
## mu[406]     7.70    0.07  2.66     3.42     5.83     7.35     9.28
## mu[407]     1.70    0.03  1.03     0.40     0.95     1.48     2.20
## mu[408]    11.65    0.09  3.35     6.07     9.32    11.23    13.69
## mu[409]     1.08    0.02  0.77     0.18     0.53     0.89     1.41
## mu[410]     1.38    0.02  0.94     0.27     0.70     1.15     1.78
## mu[411]    33.23    0.15  5.67    23.47    28.94    33.03    37.23
## mu[412]    36.58    0.15  5.97    25.66    32.40    36.13    40.52
## mu[413]     6.52    0.06  2.43     2.64     4.80     6.19     7.99
## mu[414]     1.16    0.02  0.82     0.22     0.57     0.95     1.55
## mu[415]     0.75    0.02  0.58     0.10     0.34     0.59     1.00
## mu[416]    36.94    0.14  5.55    26.51    33.33    36.70    40.29
## mu[417]     9.53    0.08  3.07     4.58     7.34     9.17    11.40
## mu[418]    15.97    0.10  3.97     9.01    13.23    15.77    18.32
## mu[419]     6.63    0.06  2.40     2.83     4.80     6.32     8.08
## mu[420]     1.58    0.02  0.96     0.35     0.87     1.39     2.02
## mu[421]    11.48    0.09  3.31     5.91     9.07    11.11    13.54
## mu[422]     1.95    0.03  1.12     0.46     1.17     1.72     2.49
## mu[423]     3.19    0.04  1.57     0.94     2.07     2.96     3.98
## mu[424]    19.68    0.12  4.64    11.78    16.30    19.26    22.65
## mu[425]     7.01    0.07  2.55     3.04     5.15     6.63     8.48
## mu[426]     3.08    0.04  1.60     0.77     1.90     2.82     4.01
## mu[427]     3.68    0.05  1.75     1.21     2.43     3.36     4.59
## mu[428]     1.12    0.02  0.82     0.20     0.53     0.88     1.47
## mu[429]     1.84    0.03  1.11     0.42     1.02     1.59     2.37
## mu[430]     5.95    0.06  2.40     2.34     4.17     5.55     7.34
## mu[431]     1.48    0.02  0.96     0.30     0.78     1.23     1.92
## mu[432]     5.96    0.06  2.31     2.47     4.35     5.62     7.20
## mu[433]     6.73    0.06  2.40     2.90     4.96     6.47     8.21
## mu[434]     3.24    0.04  1.65     0.92     2.00     2.95     4.14
## mu[435]     1.44    0.02  0.92     0.30     0.78     1.26     1.87
## mu[436]     1.12    0.02  0.81     0.16     0.54     0.91     1.51
## mu[437]     2.15    0.03  1.18     0.53     1.32     1.92     2.77
## mu[438]     1.36    0.02  0.94     0.25     0.71     1.15     1.74
## mu[439]     0.59    0.01  0.46     0.09     0.26     0.46     0.77
## mu[440]     3.62    0.05  1.81     1.08     2.31     3.28     4.61
## mu[441]     1.33    0.02  0.86     0.24     0.70     1.13     1.76
## mu[442]     2.38    0.03  1.32     0.61     1.44     2.14     3.00
## mu[443]     8.31    0.07  2.67     4.07     6.43     7.98     9.91
## mu[444]     0.52    0.01  0.48     0.05     0.19     0.38     0.69
## mu[445]     1.79    0.03  1.09     0.41     0.99     1.54     2.38
## mu[446]     2.16    0.03  1.33     0.44     1.17     1.84     2.84
## mu[447]     4.08    0.05  1.79     1.39     2.77     3.85     5.06
## mu[448]     1.61    0.03  0.99     0.32     0.92     1.39     2.06
## mu[449]     1.57    0.03  0.98     0.35     0.86     1.33     2.04
## mu[450]    18.79    0.11  4.10    11.82    15.78    18.42    21.39
## mu[451]     1.76    0.03  1.11     0.38     0.99     1.53     2.26
## mu[452]     3.13    0.04  1.62     0.89     1.95     2.80     3.99
## mu[453]    49.06    0.18  6.83    36.87    44.34    48.82    53.59
## mu[454]   147.76    0.31 11.83   125.41   139.77   147.44   155.28
## mu[455]    15.13    0.10  3.82     8.46    12.49    14.87    17.33
## mu[456]     2.97    0.04  1.52     0.82     1.86     2.69     3.76
## mu[457]     1.47    0.02  0.92     0.28     0.81     1.26     1.92
## mu[458]     3.44    0.04  1.74     1.03     2.16     3.14     4.37
## mu[459]     7.89    0.07  2.56     3.73     6.01     7.59     9.44
## mu[460]     1.48    0.02  0.96     0.30     0.78     1.24     1.93
## mu[461]     1.34    0.02  0.95     0.23     0.64     1.12     1.77
## mu[462]    44.02    0.17  6.56    31.76    39.77    43.60    48.12
## mu[463]     7.27    0.06  2.50     3.28     5.41     6.93     8.88
## mu[464]     0.81    0.02  0.68     0.10     0.35     0.62     1.05
## mu[465]    16.68    0.10  4.00     9.86    13.79    16.34    19.15
## mu[466]    12.92    0.09  3.50     6.99    10.41    12.69    15.04
## mu[467]     2.77    0.04  1.38     0.80     1.76     2.54     3.53
## mu[468]     0.97    0.02  0.74     0.15     0.46     0.76     1.26
## mu[469]     3.15    0.04  1.58     0.84     2.09     2.90     3.90
## mu[470]     1.43    0.02  0.95     0.27     0.73     1.20     1.86
## mu[471]     4.14    0.05  1.84     1.34     2.88     3.90     5.05
## mu[472]    12.92    0.09  3.36     6.92    10.57    12.74    14.95
## mu[473]    10.00    0.08  3.04     4.93     7.75     9.73    12.02
## mu[474]     4.48    0.05  1.91     1.63     3.10     4.20     5.52
## mu[475]   129.46    0.30 11.48   107.62   121.70   129.25   137.07
## mu[476]    10.39    0.08  3.19     5.34     8.15     9.99    12.21
## mu[477]    20.93    0.11  4.44    12.99    17.78    20.72    23.56
## mu[478]    30.70    0.15  5.69    20.59    26.76    30.33    34.10
## mu[479]     5.24    0.05  2.06     2.07     3.73     4.95     6.46
## mu[480]     1.18    0.02  0.81     0.21     0.61     0.98     1.54
## mu[481]     1.52    0.02  0.91     0.30     0.87     1.33     2.01
## mu[482]     1.94    0.03  1.16     0.43     1.11     1.69     2.48
## mu[483]     7.07    0.06  2.46     3.07     5.28     6.81     8.50
## mu[484]     6.64    0.07  2.57     2.79     4.65     6.31     8.18
## mu[485]     1.45    0.03  0.99     0.28     0.72     1.22     1.91
## mu[486]    31.65    0.14  5.38    21.78    28.02    31.37    35.08
## mu[487]     5.42    0.06  2.14     2.03     3.93     5.11     6.61
## mu[488]     1.32    0.02  0.91     0.23     0.68     1.10     1.65
## mu[489]     7.66    0.07  2.65     3.36     5.77     7.30     9.34
## mu[490]     0.91    0.02  0.73     0.13     0.42     0.70     1.15
## mu[491]     2.32    0.03  1.30     0.58     1.41     2.05     2.95
## mu[492]     2.36    0.03  1.24     0.68     1.48     2.14     2.99
## mu[493]     2.81    0.04  1.54     0.73     1.66     2.52     3.60
## mu[494]     0.94    0.02  0.69     0.15     0.45     0.76     1.26
## mu[495]    11.43    0.09  3.46     5.97     8.88    11.06    13.36
## mu[496]     0.68    0.01  0.56     0.09     0.29     0.52     0.90
## mu[497]    80.41    0.23  9.05    63.64    73.46    80.34    86.90
## mu[498]     3.90    0.05  1.77     1.33     2.57     3.66     4.85
## mu[499]     1.18    0.02  0.83     0.21     0.57     0.95     1.57
## mu[500]    27.20    0.14  5.40    17.78    23.27    26.90    30.69
## sigma       1.05    0.00  0.05     0.96     1.02     1.05     1.08
## lp__    16677.31    0.94 17.86 16642.11 16665.10 16677.25 16689.85
##            97.5% n_eff Rhat
## a[1]        1.61  1500 1.00
## a[2]        1.43  1500 1.00
## b           1.01  1500 1.00
## c[1]        0.26  1500 1.00
## c[2]       -0.21  1500 1.00
## mu[1]       7.79  1500 1.00
## mu[2]       6.76  1500 1.00
## mu[3]      10.71  1500 1.00
## mu[4]      20.24  1500 1.00
## mu[5]       4.82  1500 1.00
## mu[6]      58.81  1500 1.00
## mu[7]       8.74  1500 1.00
## mu[8]       3.14  1500 1.00
## mu[9]       5.93  1500 1.00
## mu[10]     29.71  1500 1.00
## mu[11]      2.06  1500 1.00
## mu[12]      2.09  1500 1.00
## mu[13]      3.84  1500 1.00
## mu[14]      5.05  1500 1.00
## mu[15]     24.69  1500 1.00
## mu[16]    692.29  1500 1.00
## mu[17]      3.58  1500 1.00
## mu[18]      3.72  1500 1.00
## mu[19]     11.72  1500 1.00
## mu[20]      4.71  1500 1.00
## mu[21]     10.48  1500 1.00
## mu[22]      6.69  1500 1.00
## mu[23]      6.69  1500 1.00
## mu[24]     51.11  1500 1.00
## mu[25]      6.28  1500 1.00
## mu[26]      3.75  1500 1.00
## mu[27]      9.92  1500 1.00
## mu[28]      9.20  1500 1.00
## mu[29]      7.02  1500 1.00
## mu[30]      7.50  1500 1.00
## mu[31]      5.99  1500 1.00
## mu[32]      2.94  1500 1.00
## mu[33]      7.99  1500 1.00
## mu[34]      3.25  1500 1.00
## mu[35]      5.46  1500 1.00
## mu[36]      4.92  1500 1.00
## mu[37]      8.57  1500 1.00
## mu[38]      4.46  1500 1.00
## mu[39]      4.21  1500 1.00
## mu[40]      3.84  1500 1.00
## mu[41]      9.07  1500 1.00
## mu[42]     10.52  1500 1.00
## mu[43]     17.25  1500 1.00
## mu[44]     30.99  1500 1.00
## mu[45]      3.58  1500 1.00
## mu[46]      3.03  1500 1.00
## mu[47]     10.93  1500 1.00
## mu[48]      8.37  1500 1.00
## mu[49]      4.62  1500 1.00
## mu[50]     16.05  1500 1.00
## mu[51]     61.59  1500 1.00
## mu[52]      3.65  1500 1.00
## mu[53]     10.45  1500 1.00
## mu[54]     44.65  1500 1.00
## mu[55]     34.12  1500 1.00
## mu[56]    101.70  1500 1.00
## mu[57]     20.24  1500 1.00
## mu[58]      4.00  1500 1.00
## mu[59]      8.27  1500 1.00
## mu[60]      2.68  1500 1.00
## mu[61]     19.57  1500 1.00
## mu[62]      7.42  1500 1.00
## mu[63]      1.62  1500 1.00
## mu[64]      3.35  1500 1.00
## mu[65]     20.00  1500 1.00
## mu[66]      3.16  1500 1.00
## mu[67]     25.62  1500 1.00
## mu[68]      5.40  1500 1.00
## mu[69]      4.74  1500 1.00
## mu[70]      4.12  1500 1.00
## mu[71]      4.55  1500 1.00
## mu[72]     61.76  1500 1.00
## mu[73]      4.22  1500 1.00
## mu[74]      6.77  1500 1.00
## mu[75]     22.63  1500 1.00
## mu[76]      7.74  1500 1.00
## mu[77]     44.07  1500 1.00
## mu[78]     19.51  1500 1.00
## mu[79]     15.41  1500 1.00
## mu[80]      4.40  1500 1.00
## mu[81]     12.79  1500 1.00
## mu[82]      4.59  1500 1.00
## mu[83]      5.32  1500 1.00
## mu[84]     12.32  1500 1.00
## mu[85]      7.17  1500 1.00
## mu[86]     27.99  1500 1.00
## mu[87]     18.58  1500 1.00
## mu[88]      7.59  1500 1.00
## mu[89]     31.32  1500 1.00
## mu[90]      8.88  1500 1.00
## mu[91]      9.60  1500 1.00
## mu[92]     10.80  1500 1.00
## mu[93]      6.17  1500 1.00
## mu[94]     30.81  1500 1.00
## mu[95]      3.65  1500 1.00
## mu[96]    225.92  1500 1.00
## mu[97]      7.92  1500 1.00
## mu[98]      6.90  1500 1.00
## mu[99]      8.85  1500 1.00
## mu[100]     2.45  1500 1.00
## mu[101]    10.83  1500 1.00
## mu[102]    22.22  1500 1.00
## mu[103]     6.30  1500 1.00
## mu[104]    40.91  1500 1.00
## mu[105]     7.18  1500 1.00
## mu[106]     5.12  1500 1.00
## mu[107]    23.56  1500 1.00
## mu[108]     4.65  1500 1.00
## mu[109]    52.34  1500 1.00
## mu[110]     4.68  1500 1.00
## mu[111]     9.71  1500 1.00
## mu[112]     9.59  1500 1.00
## mu[113]     2.10  1500 1.00
## mu[114]     8.73  1500 1.00
## mu[115]    69.03  1500 1.00
## mu[116]     5.92  1500 1.00
## mu[117]     3.05  1500 1.00
## mu[118]    21.46  1500 1.00
## mu[119]     4.58  1500 1.00
## mu[120]     5.04  1500 1.00
## mu[121]     6.53  1500 1.00
## mu[122]     3.56  1500 1.00
## mu[123]     8.83  1500 1.00
## mu[124]     5.98  1500 1.00
## mu[125]    46.83  1500 1.00
## mu[126]     3.63  1500 1.00
## mu[127]     7.83  1500 1.00
## mu[128]    12.99  1500 1.00
## mu[129]    12.73  1500 1.00
## mu[130]     7.20  1500 1.00
## mu[131]   104.70  1500 1.00
## mu[132]    18.90  1500 1.00
## mu[133]     4.02  1500 1.00
## mu[134]    27.30  1500 1.00
## mu[135]    17.67  1500 1.00
## mu[136]     6.02  1500 1.00
## mu[137]    13.99  1500 1.00
## mu[138]     2.68  1500 1.00
## mu[139]     9.46  1500 1.00
## mu[140]     8.01  1500 1.00
## mu[141]     2.10  1500 1.00
## mu[142]     8.41  1500 1.00
## mu[143]     6.64  1500 1.00
## mu[144]     2.19  1500 1.00
## mu[145]     4.36  1500 1.00
## mu[146]     3.17  1500 1.00
## mu[147]    15.01  1500 1.00
## mu[148]    26.11  1500 1.00
## mu[149]    33.00  1500 1.00
## mu[150]    42.95  1500 1.00
## mu[151]     3.57  1500 1.00
## mu[152]     2.66  1500 1.00
## mu[153]     4.48  1500 1.00
## mu[154]    75.35  1500 1.00
## mu[155]     4.10  1500 1.00
## mu[156]     3.40  1500 1.00
## mu[157]    17.90  1500 1.00
## mu[158]     2.84  1500 1.00
## mu[159]    19.34  1500 1.00
## mu[160]     6.80  1500 1.00
## mu[161]    28.92  1500 1.00
## mu[162]     4.79  1500 1.00
## mu[163]     9.72  1500 1.00
## mu[164]     4.76  1500 1.00
## mu[165]     3.73  1500 1.00
## mu[166]     4.12  1500 1.00
## mu[167]    24.22  1500 1.00
## mu[168]     7.85  1500 1.00
## mu[169]     5.19  1500 1.00
## mu[170]    64.16  1500 1.00
## mu[171]     6.82  1500 1.00
## mu[172]     3.73  1500 1.00
## mu[173]    15.07  1500 1.00
## mu[174]    41.16  1500 1.00
## mu[175]    19.25  1500 1.00
## mu[176]    39.88  1500 1.00
## mu[177]     2.85  1500 1.00
## mu[178]     3.10  1500 1.00
## mu[179]     3.86  1500 1.00
## mu[180]     1.68  1500 1.00
## mu[181]    15.52  1500 1.00
## mu[182]     5.25  1500 1.00
## mu[183]     4.01  1500 1.00
## mu[184]    22.40  1500 1.00
## mu[185]     7.07  1500 1.00
## mu[186]     9.54  1500 1.00
## mu[187]     4.03  1500 1.00
## mu[188]   143.73  1500 1.00
## mu[189]    11.41  1500 1.00
## mu[190]    27.73  1500 1.00
## mu[191]     4.90  1500 1.00
## mu[192]    27.76  1500 1.00
## mu[193]     6.07  1500 1.00
## mu[194]     4.22  1500 1.00
## mu[195]     2.07  1500 1.00
## mu[196]     7.28  1500 1.00
## mu[197]    82.71  1500 1.00
## mu[198]     6.95  1500 1.00
## mu[199]     8.44  1500 1.00
## mu[200]     4.58  1500 1.00
## mu[201]    12.64  1500 1.00
## mu[202]     7.66  1500 1.00
## mu[203]     4.02  1500 1.00
## mu[204]     7.59  1500 1.00
## mu[205]    13.31  1500 1.00
## mu[206]     3.14  1500 1.00
## mu[207]    50.73  1500 1.00
## mu[208]     4.24  1500 1.00
## mu[209]     6.12  1500 1.00
## mu[210]     3.77  1500 1.00
## mu[211]    15.46  1500 1.00
## mu[212]     9.96  1500 1.00
## mu[213]    24.48  1500 1.00
## mu[214]     6.11  1500 1.00
## mu[215]     2.61  1500 1.00
## mu[216]     4.94  1500 1.00
## mu[217]   108.01  1500 1.00
## mu[218]     7.43  1500 1.00
## mu[219]     5.16  1500 1.00
## mu[220]     3.07  1500 1.00
## mu[221]     6.28  1500 1.00
## mu[222]    17.46  1500 1.00
## mu[223]     4.16  1500 1.00
## mu[224]    10.52  1500 1.00
## mu[225]    11.12  1500 1.00
## mu[226]     3.26  1500 1.00
## mu[227]    37.18  1500 1.00
## mu[228]    24.56  1500 1.00
## mu[229]    92.69  1500 1.00
## mu[230]     3.18  1500 1.00
## mu[231]     8.76  1500 1.00
## mu[232]    28.46  1500 1.00
## mu[233]    51.52  1500 1.00
## mu[234]    21.02  1500 1.00
## mu[235]     7.98  1500 1.00
## mu[236]     5.75  1500 1.00
## mu[237]     3.80  1500 1.00
## mu[238]     4.36  1500 1.00
## mu[239]    10.14  1500 1.00
## mu[240]    17.38  1500 1.00
## mu[241]     9.97  1500 1.00
## mu[242]    19.22  1500 1.00
## mu[243]     9.50  1500 1.00
## mu[244]     8.24  1500 1.00
## mu[245]    24.24  1500 1.00
## mu[246]     8.74  1500 1.00
## mu[247]     5.16  1500 1.00
## mu[248]     2.01  1500 1.00
## mu[249]     9.09  1500 1.00
## mu[250]     5.07  1500 1.00
## mu[251]     7.44  1500 1.00
## mu[252]    15.80  1500 1.00
## mu[253]    14.31  1500 1.00
## mu[254]    13.74  1500 1.00
## mu[255]     6.84  1500 1.00
## mu[256]     3.72  1500 1.00
## mu[257]    14.44  1500 1.00
## mu[258]     2.03  1500 1.00
## mu[259]     5.06  1500 1.00
## mu[260]     3.81  1500 1.00
## mu[261]     2.27  1500 1.00
## mu[262]     4.84  1500 1.00
## mu[263]     7.12  1500 1.00
## mu[264]     4.02  1500 1.00
## mu[265]    11.91  1500 1.00
## mu[266]    12.12  1500 1.00
## mu[267]    98.00  1500 1.00
## mu[268]    10.52  1500 1.00
## mu[269]     2.55  1500 1.00
## mu[270]     4.91  1500 1.00
## mu[271]     8.19  1500 1.00
## mu[272]    25.20  1500 1.00
## mu[273]     3.43  1500 1.00
## mu[274]     8.49  1500 1.00
## mu[275]     2.61  1500 1.00
## mu[276]     7.31  1500 1.00
## mu[277]     3.28  1500 1.00
## mu[278]     6.09  1500 1.00
## mu[279]     7.70  1500 1.00
## mu[280]    10.13  1500 1.00
## mu[281]     2.84  1500 1.00
## mu[282]     9.27  1500 1.00
## mu[283]     9.32  1500 1.00
## mu[284]     3.67  1500 1.00
## mu[285]    11.75  1500 1.00
## mu[286]     7.81  1500 1.00
## mu[287]     7.35  1500 1.00
## mu[288]    23.91  1500 1.00
## mu[289]    23.68  1500 1.00
## mu[290]    11.52  1500 1.00
## mu[291]     6.83  1500 1.00
## mu[292]     7.09  1500 1.00
## mu[293]     6.15  1500 1.00
## mu[294]   106.50  1500 1.00
## mu[295]    24.53  1500 1.00
## mu[296]     4.90  1500 1.00
## mu[297]     9.91  1500 1.00
## mu[298]     4.98  1500 1.00
## mu[299]    81.69  1500 1.00
## mu[300]     4.15  1500 1.00
## mu[301]     5.17  1500 1.00
## mu[302]    10.82  1500 1.00
## mu[303]     4.68  1500 1.00
## mu[304]     4.72  1500 1.00
## mu[305]     2.78  1500 1.00
## mu[306]    24.13  1500 1.00
## mu[307]     2.99  1500 1.00
## mu[308]    11.06  1500 1.00
## mu[309]    82.94  1500 1.00
## mu[310]     5.51  1500 1.00
## mu[311]    18.54  1500 1.00
## mu[312]     4.62  1500 1.00
## mu[313]    50.46  1500 1.00
## mu[314]    19.08  1500 1.00
## mu[315]    10.10  1500 1.00
## mu[316]     6.21  1500 1.00
## mu[317]   291.11  1500 1.00
## mu[318]     9.69  1500 1.00
## mu[319]     4.15  1500 1.00
## mu[320]     4.50  1500 1.00
## mu[321]     4.54  1500 1.00
## mu[322]     3.54  1500 1.00
## mu[323]    11.17  1500 1.00
## mu[324]     9.36  1500 1.00
## mu[325]     7.67  1500 1.00
## mu[326]    37.63  1500 1.00
## mu[327]     7.96  1500 1.00
## mu[328]     3.24  1500 1.00
## mu[329]     4.10  1500 1.00
## mu[330]     7.16  1500 1.00
## mu[331]     6.90  1500 1.00
## mu[332]    20.81  1500 1.00
## mu[333]    70.08  1500 1.00
## mu[334]     4.81  1500 1.00
## mu[335]    97.02  1500 1.00
## mu[336]     4.90  1500 1.00
## mu[337]     8.73  1500 1.00
## mu[338]     4.17  1500 1.00
## mu[339]     6.49  1500 1.00
## mu[340]     4.49  1500 1.00
## mu[341]    14.19  1500 1.00
## mu[342]     9.78  1500 1.00
## mu[343]     6.90  1500 1.00
## mu[344]     4.68  1500 1.00
## mu[345]     7.43  1500 1.00
## mu[346]    22.05  1500 1.00
## mu[347]     4.44  1500 1.00
## mu[348]     8.92  1500 1.00
## mu[349]    13.85  1500 1.00
## mu[350]     6.00  1500 1.00
## mu[351]     3.65  1500 1.00
## mu[352]    12.70  1500 1.00
## mu[353]    10.39  1500 1.00
## mu[354]     3.77  1500 1.00
## mu[355]    31.00  1500 1.00
## mu[356]     9.88  1500 1.00
## mu[357]     7.45  1500 1.00
## mu[358]     3.14  1500 1.00
## mu[359]     7.66  1500 1.00
## mu[360]     2.32  1500 1.00
## mu[361]     6.26  1500 1.00
## mu[362]     3.66  1500 1.00
## mu[363]     8.22  1500 1.00
## mu[364]     9.91  1500 1.00
## mu[365]     7.94  1500 1.00
## mu[366]     6.92  1500 1.00
## mu[367]    59.24  1500 1.00
## mu[368]     3.52  1500 1.00
## mu[369]     2.71  1500 1.00
## mu[370]     2.88  1500 1.00
## mu[371]    14.70  1500 1.00
## mu[372]     3.36  1500 1.00
## mu[373]    22.12  1500 1.00
## mu[374]    76.40  1500 1.00
## mu[375]     4.31  1500 1.00
## mu[376]     7.95  1500 1.00
## mu[377]     7.23  1500 1.00
## mu[378]    29.91  1500 1.00
## mu[379]    28.38  1500 1.00
## mu[380]     2.50  1500 1.00
## mu[381]     7.14  1500 1.00
## mu[382]     6.29  1500 1.00
## mu[383]    20.80  1500 1.00
## mu[384]     7.20  1500 1.00
## mu[385]    31.52  1500 1.00
## mu[386]    18.53  1500 1.00
## mu[387]   226.63  1500 1.00
## mu[388]    20.71  1500 1.00
## mu[389]    10.93  1500 1.00
## mu[390]    54.21  1500 1.00
## mu[391]    22.97  1500 1.00
## mu[392]    11.33  1500 1.00
## mu[393]    12.63  1500 1.00
## mu[394]     3.27  1500 1.00
## mu[395]    26.29  1500 1.00
## mu[396]    13.68  1500 1.00
## mu[397]    16.74  1500 1.00
## mu[398]     7.10  1500 1.00
## mu[399]     5.58  1500 1.00
## mu[400]    10.15  1500 1.00
## mu[401]    15.69  1500 1.00
## mu[402]     2.86  1500 1.00
## mu[403]    16.19  1500 1.00
## mu[404]     3.98  1500 1.00
## mu[405]    79.09  1500 1.00
## mu[406]    13.89  1500 1.00
## mu[407]     4.02  1500 1.00
## mu[408]    18.73  1500 1.00
## mu[409]     3.11  1500 1.00
## mu[410]     3.85  1500 1.00
## mu[411]    45.00  1500 1.00
## mu[412]    49.19  1500 1.00
## mu[413]    12.12  1500 1.00
## mu[414]     3.20  1500 1.00
## mu[415]     2.33  1500 1.00
## mu[416]    48.35  1500 1.00
## mu[417]    16.62  1500 1.00
## mu[418]    24.59  1500 1.00
## mu[419]    12.10  1500 1.00
## mu[420]     4.16  1500 1.00
## mu[421]    18.74  1500 1.00
## mu[422]     4.87  1500 1.00
## mu[423]     6.95  1500 1.00
## mu[424]    30.30  1500 1.00
## mu[425]    12.83  1500 1.00
## mu[426]     7.07  1500 1.00
## mu[427]     7.73  1500 1.00
## mu[428]     3.24  1500 1.00
## mu[429]     4.68  1500 1.00
## mu[430]    11.66  1500 1.00
## mu[431]     3.78  1500 1.00
## mu[432]    11.30  1500 1.00
## mu[433]    12.34  1500 1.00
## mu[434]     7.29  1500 1.00
## mu[435]     3.83  1500 1.00
## mu[436]     3.19  1500 1.00
## mu[437]     5.05  1500 1.00
## mu[438]     3.95  1500 1.00
## mu[439]     1.81  1500 1.00
## mu[440]     7.95  1500 1.00
## mu[441]     3.43  1500 1.00
## mu[442]     5.70  1500 1.00
## mu[443]    14.16  1500 1.00
## mu[444]     1.84  1500 1.00
## mu[445]     4.52  1500 1.00
## mu[446]     5.48  1500 1.00
## mu[447]     8.06  1500 1.00
## mu[448]     4.15  1500 1.00
## mu[449]     4.05  1500 1.00
## mu[450]    27.60  1500 1.00
## mu[451]     4.65  1500 1.00
## mu[452]     7.21  1500 1.00
## mu[453]    63.03  1500 1.00
## mu[454]   171.70  1500 1.00
## mu[455]    23.62  1500 1.00
## mu[456]     6.73  1500 1.00
## mu[457]     3.71  1500 1.00
## mu[458]     7.52  1500 1.00
## mu[459]    13.42  1500 1.00
## mu[460]     3.94  1500 1.00
## mu[461]     3.63  1500 1.00
## mu[462]    57.39  1500 1.00
## mu[463]    12.88  1500 1.00
## mu[464]     2.60  1500 1.00
## mu[465]    25.26  1500 1.00
## mu[466]    20.70  1500 1.00
## mu[467]     6.13  1500 1.00
## mu[468]     2.99  1500 1.00
## mu[469]     6.98  1500 1.00
## mu[470]     3.94  1500 1.00
## mu[471]     8.74  1500 1.00
## mu[472]    20.33  1500 1.00
## mu[473]    16.77  1500 1.00
## mu[474]     9.03  1500 1.00
## mu[475]   152.79  1500 1.00
## mu[476]    17.47  1500 1.00
## mu[477]    31.12  1500 1.00
## mu[478]    43.32  1500 1.00
## mu[479]     9.95  1500 1.00
## mu[480]     3.27  1500 1.00
## mu[481]     3.69  1500 1.00
## mu[482]     5.05  1500 1.00
## mu[483]    12.77  1500 1.00
## mu[484]    12.63  1500 1.00
## mu[485]     4.07  1500 1.00
## mu[486]    43.12  1500 1.00
## mu[487]    10.51  1500 1.00
## mu[488]     3.92  1500 1.00
## mu[489]    13.56  1500 1.00
## mu[490]     2.76  1500 1.00
## mu[491]     5.81  1500 1.00
## mu[492]     5.38  1500 1.00
## mu[493]     6.36  1500 1.00
## mu[494]     2.73  1500 1.00
## mu[495]    19.05  1500 1.00
## mu[496]     2.13  1500 1.00
## mu[497]    98.00  1500 1.00
## mu[498]     7.92  1500 1.00
## mu[499]     3.33  1500 1.00
## mu[500]    38.58  1500 1.00
## sigma       1.14   606 1.01
## lp__    16711.80   361 1.01
## 
## Samples were drawn using NUTS(diag_e) at Mon Jan 29 22:17:03 2018.
## For each parameter, n_eff is a crude measure of effective sample size,
## and Rhat is the potential scale reduction factor on split chains (at 
## convergence, Rhat=1).

plot of chunk trace_fullmodel

How’d we do now?

We still haven’t looked to see how close the true parameters were to the inferred values. Here are posterior distributions from the full model, with the true values in red. plot of chunk true_fit

Posterior predictive simulations, again

Now we cover the true data

plot of chunk plot_post_sims2

Model comparison

How to compare the two models?

Two models:

  1. counts ~ poisson(exp(a + b * age + c * exposure))

  2. counts ~ poisson(logNormal(a + b * age + c * exposure))

We just saw some plots that showed that the true data lay outside the range of the simulated data from (1) but not (2).

That was not a formal test.

We need a statistic!

Brainstorm: how can we quantify what we just saw?

Goal: come up with a single number that quantifies how much the observed data “looks like” the posterior predictive samples.

Then, the model with a better score fits better.

plot of chunk plot_model_fit

Same plot, zoomed in:

plot of chunk plot_model_fit2

Implementation

The “simple” model, that did not model overdispersion has a goodness of fit score of 4.6615927, substantially larger than the lognormal model, which had a score of 1.0362712. The score communicates how far the observed data are from the mean of the simulated data, in units of standard deviations.

But does the model fit?

To see if model 2 actually does describe the data well, we’ll find the distribution of goodness-of-fit scores based on simulation: simulate some more datasets, compute the GOF score for each, and see where the observed value lies within that distribution.

On the next slide is a histogram of 100 GOF scores from simulated data; the red line shows the observed value.

plot of chunk gof_sims

Stan interlude

The important program blocks

data {
    // what we know: the input
    // declarations only
}
parameters {
    // what we want to know about:
    // defines the space Stan random walks in
    // declarations only
}
model {
    // stuff to calculate the priors and the likelihoods
    // happens every step
}

The program blocks

functions {
    // user-defined functions
}
data {
    // what we know: the input
    // declarations only
}
transformed data {
    // calculations to do once, at the start
}
parameters {
    // what we want to know about:
    // defines the space Stan random walks in
    // declarations only
}
transformed parameters {
    // other things that we want the posterior distribution of
    // happens every step
}
model {
    // stuff to calculate the priors and the likelihoods
    // happens every step
}
generated quantities {
    // more things we want the posterior distribution of
    // but that don't affect the random walk
}

On priors

Under the hood,

    z ~ poisson(mu);

is equivalent to

    target += poisson_lpdf(z | mu);

(lpdf = log posterior density function).

So, if you don’t put a prior on something, it implicitly has a uniform prior (i.e., a flat prior).

Error messages

These are important. Pay attention to them, and fix the problems.

Parameterization matters

More on this later.