Hi all,
Can someone tell me what this error (at the bottom) is about. The error continues until the program seizes up.
Thanks,
David
title: “Models for Count Data”
subtitle: “EP 763: Regression Models in Education”
author: “David Kaplan”
output: pdf_document
knitr::opts_chunk$set(echo = TRUE)
library(rstan)
library(bayesplot)
Poisson Regression
School administrators study the attendance behavior of high school juniors
at two schools. Predictors of the number of days of absence include gender
of the student and standardized test scores in math and language arts.
poissonex <- read.csv("~/desktop/poissonreg.csv",header=T)
data.list <- with(poissonex, list(daysabs=daysabs, math=math, langarts=langarts, male=male, N = nrow(poissonex)))
Plot histograms of daily absentee data
attach(poissonex)
hist(daysabs,breaks=150,xlim=c(0,50), col="gray")
modelString = "
data {
int<lower=0> N;
real math[N];
real langarts[N];
real male[N];
int<lower=0> daysabs[N];
}
parameters { // Cute trick to give all of the parameters the same prior
vector[4] b;
}
transformed parameters {
real mu[N];
for (n in 1:N)
mu[n] = exp(b[1] + b[2]*math[n] + b[3]*langarts[n] +
b[4]*male[n]);
}
model {
for (n in 1:N)
daysabs[n] ~ poisson(mu[n]);
b ~ normal(0, 1);
}
generated quantities {
int<lower=0> daysabs_pred[N];
real log_lik[N];
for (n in 1:N) {
daysabs_pred[n] = poisson_rng(mu[n]);
log_lik[n] = poisson_lpmf(daysabs[n] | mu[n]);
}
}
"
Start estimation
nChains = 2
nIter= 3000
thinSteps = 10
burnInSteps = floor(nIter/2)
daysabs = data.list$daysabs
PoissRegfit = stan(data=data.list,model_code=modelString,chains=nChains,
iter=nIter,warmup=burnInSteps,thin=thinSteps)
SAMPLING FOR MODEL ‘89098a1c1b53b80a32e60b991eef32bb’ NOW (CHAIN 1).
Chain 1:
Chain 1: Gradient evaluation took 8.7e-05 seconds
Chain 1: 1000 transitions using 10 leapfrog steps per transition would take 0.87 seconds.
Chain 1: Adjust your expectations accordingly!
Chain 1:
Chain 1:
Chain 1: Iteration: 1 / 3000 [ 0%] (Warmup)
Chain 1: Exception: poisson_rng: Rate parameter is 9.73758e+38, but must be less than 1.07374e+09 (in ‘model1fba7e50c325_89098a1c1b53b80a32e60b991eef32bb’ at line 29)