Let’s try one. You think that students sleep less before exams. You ask 10 students to keep a log of the number of hours they sleep before and after a midterm exam. Here are the data.

Here’s the output from a computer package.

Answer the following questions about this test:

1. What types of groups are in this design?
2. What does the mean difference of –2.300 refer to?
3. Do we reject or fail to reject the Null Hypothesis? Explain.