This test is to be written in the BSB Student Technology Centre. The duration of the test is 2 hours.
Any books, notes and aids are permitted.
Analyze the Age of Menarche data (data frame menarche in the MASS library). Compare probit and complementary log-log analyses. Use ANOVA tables and residual plots to discuss the adequacy of the fit. Give a 95% confidence interval for the median age at menarche.
Put the file mydata.txt into your R working directory and import it with mydata <- dget("mydata.txt"). Fit a simple linear regression of y on x in the following ways and use ANOVA tables and residual plots to decide which is the best fit: (a) gamma error with inverse link, (b) normal error with identity link, (c) normal error with inverse link. For (a) give an estimate of the gamma shape parameter; for (b) and (c) give an estimate of the normal variance.