7. A health psychologist conducted an experiment in which participants watched a film that either did or did not include a person being injured because of not wearing a seat belt. A week later, as part of a seemingly different study, these same participants reported how important they thought it was to wear seat belts. The 22 participants who had seen the injury film gave a mean rating of 8.3, with an estimated population standard deviation of 1.6. The 30 participants in the control condition had a mean of 7.4 with an estimated population standard deviation of 2.2. Using the .01 significance level, does seeing a movie where a person gets injured due to not wearing a seat belt make attitudes more positive towards seat belt usage?
Population 1: people who watch a movie that includes a person who gets injured due to not wearing a seat belt.
Population 2: people who watch a movie that does not include a person who gets injured due to not wearing a seat belt.
Research hypothesis: People who watch a movie where a person gets injured due to not wearing a seat belt make more positive attitude towards seat belt usage. ($\mu_1 > \mu_2$)
Null hypothesis: People who watch a movie where a person gets injured due to not wearing a seat belt did not make more positive attitude towards seat belt usage. ($\mu_1 \leq \mu_2$)
Step 2: Determine the characteristics of the comparison distribution.
The mean of the comparison distribution:
The standard deviation of the comparison distribution ($S_E$):
(show your work)
The shape of the distribution.
Step 3: Determine the cutoff sample score (critical value) on the comparison distribution at which the null hypothesis should be rejected.
Step 4: Determine your sample's score on the comparison distribution.
Step 5: Decide whether to reject the null hypothesis.
Additional question: What is the effect size of this study? Compute the effect size. Is it a small, medium, or large effect?