A clever graduate, grace n. Poise, hypothesizes that people under 30 are more humorous than people over 30. She tests this hypothesis by randomly selecting 4 people over 30 from the telephone book and 4 people under 30 from the university registration lists. She gives each research participant the humorous speech scale, which measures humor on a Likert-type scale from 1-10. The scores are listed below.

ppl under 30 Ppl over 30

6 5

7 6

10 2

9 3

what are the degrees of freedom?