Suppose you are interested in buying or selling products through online auctions. What circumstances are good for buying? What circumstances are good for selling? To investigate this problem, a former SMU professor collected data on winning bid prices forcomputers purchased through online auctions. Several years ago, 488 eBay auctions of a popular model of Dell Latitude were recorded over a three-month period. The data (in the worksheet labeled "Data") include: (1) winning bid: the winning bid for a particular auction, (2) day: the day of the week that the auction closed, (3) # bids: the number of bids in the auction, (4) # auctions: the number of auctions that closed that day for the same laptop, and (5) rank-in-day: the rank of the auction within a day (i.e., the order that it end among laptop auctions on that day). The day of the week is coded using dummy variables; sun = 1 if the auction closed on a Sunday (0 otherwise), mon= 1 if it closed on a Monday (0 otherwise), etc.

a. Do the variables included in the model collectively explain a significant amount of the variation in winning bids? Cite the appropriate test, test statistic, p-value, and your conclusion at the a = .05 level.

b. Is there a relationship between the winning bid price and the rank of the auction (in this model)? Cite an appropriate test, your test statistic, p-value, and your conclusion at the a = .05 level.

c. What is the price difference between a Dell laptop auctioned on Saturday and one auctioned on Sunday (all other things remaining equal)? Is this difference $0? Cite the relevant test statistic, the p-value, and your conclusion at the a = .05level.