4. Refer to the previous exercise. Allow overdispersion by fitting the neg- ative binomial log linear model. (a) Report the prediction equation and the estimate of the dispersion parameter and its SE. Is there evidence this model gives a better fit than the Poisson model? (b) Construct a 95% confidence interval for8 . Compare it with the one in (c) in the previous exercise. Interpret, and explain why the interval is wider with the negative binomial model