1. The reaction of an individual to a stimulus in apsychological experiment may take one of the two forms: A or B. Anexperimenter wishes to estimate the true proportion of people whowill react in manner A. How many people must she include in thesample if she wants to estimate the true proportion with a 85%confidence interval of length 0. 06? Also, assume that a pilotstudy had revealed the proportion to be somewhere around 15%.
2. Suppose the sample mean lifetime of twenty-five batteries ofa certain type (say Type A) was found to be 4. 1 hours with acorresponding standard deviation 0. 87 hours. Similarly, the samplemean lifetime of twenty-two batteries of another type (say Type B)was found to be 4. 9 hours with a corresponding standard deviation0. 42 hours. At a significance level of alpha = 0. 02, is thereenough evidence that Type A batteries is inferior to Type B?
