A popular consumer staple was displayed in different locations in the same aisle of a grocery store to determine what, if any, effect different placement might have on its sales. The product was placed at one of three heights on the aisle—low, medium, and high—and at one of three locations in the store—at the front of the store, at the middle of the store, or at the rear of the store. The number of units sold of the product at the various height and distance combinations was recorded each week for five weeks. The following results were obtained:

Front Middle Rear Low 125 195 126 143 150 136 150 160 129 138 195 136 149 162 147 Medium 141 186 128 137 161 133 145 157 148 150 165 145 130 194 141 High 129 157 149 141 152 137 148 186 138 130 164 126 137 176 138

a. At the 0.10 level of significance, is there an interaction effect?

b. At the 0.10 level of significance, does the height of the product’s placement have an effect on the product’s mean sales?

c. At the 0.10 level of significance, does the location in the store have an effect on the product’s mean sales?