Shank's, Inc., a nationwide advertising firm, wants to know whether the size of an advertisement and the color of the advertisement make a difference in the response of magazine readers. A random sample of readers is shown ads of four different colors and three different sizes. Each reader is asked to give the particular combination of size and color a rating between 1 and 10. Assume that the ratings are approximately normally distributed. The rating for each combination is shown in the table following (for example, the rating for a small red ad is 2). Is there a difference in the effectiveness of an advertisement by color and by size? Use the 0.05 level of significance.
Color of Ad
Size of Ad
Red Blue Orange Green
Small 2 3 3 6
Medium 3 5 6 7
Large 6 7 8 8