A researcher aims to evaluate the effect of aerobic exercise training on Peak Expiratory Flow Rate (PEFR) in healthy young men. He recruited twenty healthy male students aged 18-21 years. The subjects participated in a 16 weeks aerobic exercise plan. The PEFR was recorded in Liter Per Minute (l/min) before the commencement of training and at the end of training. We want to examine whether the difference in the PEFR is just chance variation or not. Suppose that we observe the results in Table 1 (see the last page) from SAS when we analyzed our data using the UNIVARIATE procedure.

1. What is the purpose of a Paired t-Test and why is it the appropriate statistical test to conduct in this situation?

2) State the Null and Alternative hypotheses.

3. We can use information from the SAS output to calculate a 95% CI for the estimate of the mean difference. Towards the top of the table, we find the N of 20 and the mean difference of -87.8683 l/min. SAS has also calculated the standard deviation (54.0132) for us. We do need to determine the confidence factor of the difference or t _(n-1) by going to Table A-3 in the textbook. Calculate and report the 95% CI. [Show your work.]

4) We can also use that information to calculate the test statistic (i.e. the t-score). Dawson and Trapp note the t-score formula as:

5) Based on what you calculated in question 4 above, what conclusion would you make about the null hypothesis (i.e. would you Reject or Fail to Reject the null hypothesis)? What is your interpretation of the test statistic?

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1 The Paired Samples t Test compares two means that are from the same individual object or related u... View the full answer