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, steeping, working, and leisure. Any activity is pull into one of the four categories, so that for each student, the sum of hours in the four activities must be 168. sav = beta_0 + beta_1 study + beta_2 sleep + beta_3 work + beta_4 leisure + u does it make sense to hold sleep, work, and leisure fixed, while changing study? Does it make sense to hold sleep, work, und leisure fixed, while changing study? Explain why this model violates Assumption MLR.3. How could you reformulate the model so that its parameter has a useful interpretation and it satisfies Assumption MLR.3