A study was conducted to determine if differences in new textbook prices exist between on-campus bookstores, off-campus bookstores, and Internet bookstores. To control for differences in textbook prices that might exist across disciplines, the study randomly selected 12 textbooks and recorded the price of each of the 12 books at each of the three retailers. You may assume normality and equal-variance assumptions have been met. The partially completed ANOVA table based on the study's findings is shown here:

a. Complete the ANOVA table by filling in the missing sums of squares, the degrees of freedom for each source, the mean square, and the calculated F -test statistic for each possible hypothesis test.
b. Based on the study's findings, was it correct to block for differences in textbooks? Conduct the appropriate test at the α = 0.10 level of significance.
c. Based on the study's findings, can it be concluded that there is a difference in the average price of textbooks across the three retail outlets? Conduct the appropriate hypothesis test at the α = 0.10 level of significance.

ANOVA Source of Variation SS df MSF Textbooks Retailer Error Total 16,624 2.4 17,477.6