A researcher believes exercise reduces anxiety in women. She identifies a group of women who had not exercised before but are now planning to begin exercising. She gives them a 50-item anxiety inventory before they begin exercising and administers it again after 6 months of exercising. The anxiety inventory is measured on an interval scale and higher numbers indicate higher anxiety. In addition, scores on the inventory are normally distributed. The scores appear below.
Before – After
46 – 44
41 – 40
42 – 39
47 – 46
43 – 42
45 – 43
a) What statistical test should be used to analyze these data?
b) Identify Ho and Ha for this study.
c) Conduct the appropriate analysis.
d) Should Ho be rejected? What should the researcher conclude?
e) If significant, compute the effect size and interpret this.