12) Researchers examined children's recall and recognition of television advertisements. Two groups of children were shown a 60-second commercial. One group (the A/V group) was shown the ad with both audio and video and the second group (the video only group) was shown only the video portion of the commercial. After viewing the commercial, the children were asked to recall 10 specific items from the ad. Twenty children were assigned to video only group and another independent sample of 20 children were assigned to A/V group. For video only group the mean was 3.70 with a standard deviation of 1.98. For A/V group the mean was 3.30 with a standard deviation of 2.13. a) Find a 90% confidence interval for the difference in mean recalls between video only group and A/V group. Your