Question

An investigator theorizes that people who exercise regularly will have mean systolic blood pressure levels that are significantly different from those of people who do not participate in a regular exercise program. To test this idea, the investigator randomly assigns 21 subjects to an exercise program for 10 weeks and 21 subjects to a non-exercise comparison group. After ten weeks, the mean systolic blood pressure of subjects in the exercise group is 132 and the standard deviation is 10. After the same time period, the mean systolic blood pressure of subjects in the non-exercise group is 127 and the standard deviation is 9.0. Test the investigator's theory using an alpha level of 0.05.

a. Define the null and alternative hypotheses, test statistic and reject region.

b. Compute the test statistic using the data provided and draw a conclusion about the test.

c. Compute the p-value and draw a conclusion about the test. (Estimate the p-value using the probability tables or use Excel to calculate it exactly. Clearly indicate your solution method.)

d. Compute the confidence interval related to this hypothesis test and draw a conclusion about the results.

e. Phrase your conclusions from b, c and d in “English.” In other words, how would you explain the results to your boss without using the term “null hypothesis?” f. Does performing a one-sided versus a two-sided test impact your conclusions? Explain.

Answer 1