Case 182Apple Appliance Stores

An experiment using a randomized design was conducted by the Apple Appliance chain of 300 retail stores. Four levels of advertising provided the experimental treatment: none, low, medium, and high. In addition, the stores were divided by store size into small, intermediate, and large. A random sample of eight stores was taken from each of the three storesize groups. Each set of eight stores was divided randomly into four groups of two stores for the experimental treatment, as summarized in Table 18.7.

TABLE 18.2 Research Design Store size Small Medium Large Total None 2 2 2 Low 2 Advertising level Medium 2 High CO N TotalLarge stores Medium stores Small stores es changeTABLE 18.8 Analysis of Variance of Sales Changes Source of variation Sum of squares Degrees of freedom (df) Mean sum of squares F-ratio Advertising 360 3 120 3.02 Store size 88 2 44 1.1 Interaction 984 O 164 4.16 Unexplained variation 480 12 40 Total 1,912 23 Significant at the .10 level. Significant at the .05 level