Researchers examined a large number of fish to determine the prevalence of para- sites. The dataset (parasite.txt) includes the variables Intensity (i.e., the number of parasites), Area (a categorical variable), Year (to be treated as categorical), and Length of the fish. (a) Fit a Poisson model with log link to the data with area, year, and length as predictors. Interpret each model parameter. (b) Test for goodness of fit of the model in (a) and state conclusions. (c) Researchers suspect that there may be two strains of fish, one that is susceptible to parasites and one that is not. Without knowing which fish are susceptible, this could be regarded as a zero-inflated model. Building on the model in (a) (using the same predictors), fit an appropriate model to the data that can account for extra zeros. Provide an interpretation for each model parameter in terms of the problem.