A health psychologist wants to test the effectiveness of a new stress-reduction method. In the general population, stress level is normally distributed with μ = 40 and σ = 10. 40 randomly selected people are trained in the method; the mean score afterward is 36.

6. Restate question as a research hypothesis and a null hypothesis about the populations.

Population 1:

Population 2:

Research hypothesis:

Null hypothesis:

7. Determine the characteristics of the comparison distribution.

8. Determine the cutoff sample score (or Z score) on the comparison distribution at which the null hypothesis should be rejected at p < .01.