9.17 Children's recall of TV ads. Children's recall and rec- ognition of television advertisements was studied in the Journal of Advertising (Spring 2006). Two groups of chil- dren were shown a 60-second commercial for Sunkist FunFruit Rock-n-Roll Shapes. One group (the A/V group) was shown the ad with both audio and video; the second group (the video-only group) was shown only the video portion of the commercial. Following the viewing, the children were asked to recall 10 specific items from the ad. The number of items recalled correctly by each child is summarized in the accompanying table. The re- searchers theorized that "children who receive an audio- visual presentation will have the same level of mean re- call of ad information as those who receive only the visual aspects of the ad." Video-Only Group n1 = 20 x1 x = 3.70 $11.98 A/V Group n2 == 20 X2 = 3.30 $2 = 2.13 Based on Maher, J. K., Hu, M. Y., and Kolbe, R. H. "Children's recall of television ad elements." Journal of Advertising, Vol. 35, No. 1, Spring 2006 (Table 1). a. Set up the appropriate null and alternative hypotheses to test the researchers' theory. b. Find the value of the test statistic. c. Give the rejection region for a = .10. d. Make the appropriate inference. What can you say about the researchers' theory? e. The researchers reported the p-value of the test as p-value .62. Interpret this result. f. What conditions are required for the inference to be valid?