For Each of the Following Studies, Say Whether You Would

For each of the following studies, say whether you would use a t test for a single sample, t test for dependent means, or a t test for independent means.
(a)A psychology researcher randomly assigns a group of 50 high school students to receive a new assertiveness training program and 45 other high school students to receive the standard after-school program that focuses on social skills. She later measures how well each group performs on a measure of interpersonal assertiveness.
(b)A psychologist measures 100 patients in terms of their anxiety levels before and after undergoing a newly developed treatment.
(c)The coach of your college football team conducts an informal survey showing that members of the team study an average of 3.5 hours per day. The coach makes the claim that this is equivalent to the amount of time students at the college study in general. You feel that the coach is incorrect. You randomly select 50 students from the college and ask them how much they study each day. Your result is that these 50 students study an average of 5.2 hours per day.
(d)A researcher tests the memory scores of each of a group of 15 students twice, once while in a very noisy room and once while in a quiet room. She then compares the scores.
(e)A researcher measures the intelligence of college students (n = 25)who are first born in their families compared to those who were born last in their families (n = 40).