Question: Two diets were given to samples of pigs over a period of time, and the following weight gains (in lbs) were recorded.
Suppose we assume the normal regression model for these data.
(a) Produce a side-by-side boxplot for the data.
(b) Plot the standardized residuals against Diet. Also produce a normal probability plot of the standardized residuals. Does this give you grounds for concern that the model assumptions are incorrect?
(c) Carry out a one-way ANOVA to test for a difference between the conditional means of Y given Diet(d) Construct 0.95-confidence intervals for differences between the means.