A researcher would like to determine if relaxation training affects the number of headaches for chronic headache
sufferers. For a week prior to training, each participant records the number of headaches suffered. Participants then receive relaxation training and for the week following training the number of headaches is again measured. The data are as follows:
Before, After: 6,4 5,1 3,3 3,1 6,2 2,1 4,3 4,2
a. Do the results indicate a significant difference? Use a two-tailed test with α = .05. State the null hypothesis and the tcritical you will use to evaluate the null hypothesis.
b. Compute Cohen’s d and r2 to measure the size of the effect. Conclude with a separate summary statement for each measure of effect size that is appropriate for publication in a scientific journal.
Statistics and Probability