iii. An engineer suggests that model (1) is not sufficient because xl, x2 and x3 may have interaction effects on the retail price. Test if this is the case. iv. If he is only concerned if x4 and x6 in...

iii. An engineer suggests that model (1) is not sufficient because xl, x2 and x3 may have interaction effects on the retail price. Test if this is the case. iv. If he is only concerned if x4 and x6 in model (1) should be there together or not, implement, an appropriate test for him. v. Run an exhaustive variable selection algorithm for model (1) using BIC and Cp, and make some suggestions to simply the current model. vi. Run stepwise regression using AIC for model (1). Does this give you the same results as in the previous part? Which would make more sense? Explain why. 4. An avid fan of the PGA tour with limited background in statistics has sought your help in answering one of the age-old questions in golf. namely, what is the relative importance of each different aspect of the game on average prize money in professional golf ? The following data on the top 196 tour players in 2006 can be found in the file pgatour2006.csv on the eLC: Y, PrizeMoney = average prize money_per tournament