For Problem 6.8,

(a) Fit the corresponding negative binomial model with the same linear predictor.

(b) Compare the analysis between part (a) and that from Problem 6.8.

6.8 For the Sexual Health pilot study, consider modeling the number of unprotected vagi- nal sex behaviors during the three month period of the study as a function of three predictors, HIV knowledge, depression, and baseline number of unprotected vaginal sex (VAGWOCT1). (a) Fit the Poisson log-linear model. (b) Use the deviance and Pearson statistics to examine whether there is overdisper- sion in the data. (c) Does the model have an inflated zero issue?