A high school counselor wanted to know if tenth-graders at her high school tend to have more free time than the twelfth-graders. She took random samples of 25 tenth-graders and 23 twelfth-graders. Each student was asked to record the amount of free time he or she had in a typical week. The mean for the tenth-graders was found to be 29 hours of free time per week with a standard deviation of 7.0 hours. The mean amount of free time per week for students in the twelfth grade was 22 hours, with a standard deviation of 6.2 hours. Assume that the standard deviations of the two populations are equal and regularly distributed.
