STATS500 Homework 5 Solved

This homework is optional. You do NOT need to turn it in. However, if you turn it in, the score can be used to replace the lowest value of those contributing homework scores if it is lower than the core of HW #5. The contributing homework scores are those non-optional homework scores after the lowest score being dropped.

1. Revisiting the teengamb dataset (data(teengamb)). Consider a lin- ear regression model of Ylog = log(teengamb$gamble + 1) on sex, status, income and verbal. Using the codes from the classnotes to produce partial regression and partial residual plots for the predictor verbal. Is it appropriate to claim that Y has a linear relationship with verbaladjusted for the existence of other predictors in the model?
2. For the teengamb problem, use the Yorg and Ylog and the correspond- ing regression models to answer the following questions.

   (a) Check for and report large leverage points.

   (b) Would the leverage values differ for Yorg and Ylog models, ex- plain.

3. For the teengamb problem, use the Ylog and the corresponding re- gression model to answer the following questions.

   (a) Check for and report outliers.

   (b) Check for influential points. Please briefly comment on the rela- tionship of the Cook’s distances to residuals and leverage levels for the two data points with the largest Cook’s distances.