Question: Exercise 6: In a study relating college grade point average to time spent in various activities, you distribute a survey to several students. The students are asked how many hours they spend each week in four activities: studying, sleeping, working, and leisure. Any activity is put into one of the four categories, so that for each student, the sum of hours in the four activities must be 168 (=24 *7).

(i) Interpret the coefficient on study. Does this interpretation make sense?

(ii) Explain why this model violates assumption 4

(iii) How could you reformulate the model so that its parameters have a useful interpretation and it satisfies assumption 4 ?