Class Example No. 1
A researcher sets out to test his belief that the promise of a reward for good performance affects motivation and hence scores on a performance test. She uses the Block Design subtest of the WAIS-II.
Two groups are randomly selected from a population of freshmen college students. Students in Group A are promised that doing well on the subtest will excuse them from their next statistics exam. Students in Group B are told nothing.
The scores of the two groups on the Block Design subtest are:
| Group A | Group B |
| 15 | 10 |
| 12 | 9 |
| 11 | 8 |
| 10 | 8 |
| 10 | 8 |
| 10 | 8 |
| 10 | 8 |
| 9 | 8 |
| 8 | 7 |
| 5 | 6 |
What is the null hypothesis?
Did the researcher support her research hypothesis?