elijah bailey is the current mpa director. he is interested in how long it takes graduate students to complete the mpa program. he takes a random sample of 30 mpa alums and asks them how many months it took for them to complete their program. elijah finds that, for his sample of 30 alums, the average number of months was 27. he calculates the sample standard deviation to be 4. if the department head, trillian astra, wants a 95% level of confidence for the estimate of the average program length, what would elijah tell her?