11.69 In a study of memory recall, eight students from a large psychology class were selected at random and given 10 minutes to memorize a list of 20 nonsense words. Each was asked to list as many of the words as he or she could remember both 1 hour and 24 hours later. The data are as shown in the accompanying table.

Is there evidence to suggest that the mean number of words recalled after 1 hour exceeds the mean recall after 24 hours by more than 3? Use a level .01 test.

Subject 1 2 3 4 5 6 7 8 1 hour later 14 12 18 7 11 9 16 15 24 hour later 10 4 14 6 9 6 12 12