Research suggests that customers think that a product is of high quality if it is heavily advertised. An experiment designed to explore this idea is collected quality ratings (on a 1 to 7 scale) of a new line of take-home refrigerated entrees based on reading a magazine ad. Three groups were compared. The first group?s ad contained information that would Undermine (n=55) the expected positive association between quality and advertising; the second group?s ad contained information that would Affirm (n=36) the association; and the third group was a Control (n=36).

Interpret the results of the analysis summarized in the following table:

a. What is the within group sum of squares for this analysis? Explain how you obtain your answer.

b. What is the within group mean squares for this analysis? Explain how you obtain your answer.

c. At the 0.05 level of significance, is there evidence of a difference in the mean ratios for the 3 ads? Explain how you obtain your answer.

Source Advertisements Within (Error) Total df 124 SS 18.83 95.21 MS 9.41 F 15.28 PR>F 0.00001