QUESTION 1:

• Draw and shade the distribution
• Relevant formulas (if any)
• Rearrangement of formulas (if needed)
• Concluding statements

1. A researcher develops a social anxiety inventory for which the mean score in the general population is expected to be 50, with higher scores indicating greater social anxiety. The researcher hypothesizes that computer programmers are more socially anxious than the general population. To test this hypothesis, the social anxiety inventory is administered to a randomly-selected sample of 40computer programmers, for whom the mean score is 60 with a standard deviation of 15. Determine whether the sample of computer programmers experience more social anxiety than the general population (one-tailed test with alpha = .01).

2. The Ontario High School Board changed its curriculum so that students would graduate after 12 years of schooling instead of 13. In the transition year moving to this new system, Grade 12 and 13 students graduated high school at the same time. A group of researchers was interested in studying the potential effects of being part of the resulting "double cohort" on cumulative grade averages of these students in their first year at a particular university. Prior to the arrival of the double cohort, first-year cumulative averages at the university had a mean of 68 with a standard deviation of 8. In a random sample of 40 double cohort students at the university, the mean was 65 with a standard deviation of 7. Conduct an appropriate two-tailed hypothesis test with alpha = .05.

3. Report and interpret an effect size for the test in question two.

4. How much power does the test in question two have?

5. Construct an 80% confidence interval around the sample mean from question two. How would you interpret this interval?

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