Could I please get some help with this question?

A high school counselor wanted to know if tenth-graders at her high school tend to have the same free time as 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. For the twelfth-graders, the mean was 22 hours of free time per week with a standard deviation of 6.2 hours. Assume that the two populations are approximately normally distributed with unknown but equal standard deviations.

1. Make a 90% confidence interval for the difference between the corresponding population means.
2. Test at a 5% significance level whether the two population means are different.