A travel agent wanted to know whether the price (in dollars) of Marriott, Hyatt, and Sheraton Hotels differed significantly. She knew that location of the hotel is a factor in determining price, so she blocked each hotel by location. After randomly selecting six cities and obtaining the room rate for each hotel, she obtained the following data:

(a) Normal probability plots for each treatment indicate that the requirement of normality is satisfied. Verify that the requirement of equal population variances for each treatment is satisfied.
(b) Is there sufficient evidence that the mean cost of the room is different among the three hotel chains at the a = 0.05 level of significance?
(c) If the null hypothesis from part (b) was rejected, use Tukey's test to determine which pairwise means differ using a familywise error rate of a = 0.05.