Refer to the data in Table 12-14 on diabetic patients and the development of retinopathy.

(a) Develop a regression model to predict the probability of development of retinopathy based on years of diabetes and gender of person. Is the model significant at α = 0.05?

(b) Is the model developed in part

(a) better than that developed in Exercise 12-16?

Comment.

(c) Interpret the odds ratio associated with the predictors.

(d) Find a 95% confidence interval for the mean probability of developing retinopathy for males who have had diabetes for 15 years. What is the corresponding 95% confidence interval for females?