20 high school Spanish teachers attended an intensive summer course designed to improve their listening skills. They took the MLA listening test both before and after the course. Before the course,...

20 high school Spanish teachers attended an intensive summer course designed to improve their listening skills. They took the MLA listening test both before and after the course. Before the course, they had a mean of 27.3 with s=5.04. After the course, they had a mean of 28.75 with s=4.74. We want to know if the course improves scores.

a-   State an appropriate Ho and Ha.

b-   Carry out a test. Can you reject at the 5% significance level? at the 1% level?