The retailing manager of a supermarket chain wants to determine whether product location has any effect on sale of pet toys. Three different aisle locations are being considered: front, middle, and rear. A random sample of 18 stores is selected with 6 stores randomly assigned to each aisle location. The size of the display area and price of the product are constant for all stores. At the end of a 1-month trial period, the sales volumes (in thousands of dollars) of the product in each store were as follows: Berenson, Levine, and Krehbiel (2002, 405). AISLE LOCATION Front 8.6 7.2 5.4 6.2 5.0 4.0 Middle 3.2 2.4 2.0 1.4 1.8 1.6 Rear 4.6 6.0 4.0 2.8 2.2 2.8 a. At the 5% level of significance, is there evidence of a significant difference in b. If appropriate, which aisle locations appear to differ significantly in average c At the 5% level of significance, is there evidence of a significant difference in the average sales among the various aisle locations? sales? variation in sales among the various aisle locations?