A researcher is interested in whether listening to music aids or hinders test-performance. To control for differences in cognitive level, this researcher decides to employ a within-participants design. He picks a random sample of participants and has them study different material of equal difficulty in both the music as well as no music conditions. Participants take a 20-item quiz on the material. The table below shows the scores on the quiz. The study is totally counter balanced to control for order effects. The scores obtained are calculated on an interval-ratio scale and are normally distributed.
Music No Music
17 17
16 18
15 17
16 17
18 19
18 18
a. What statistical test must be employed to examine the data?
b. Is this a one- or two tailed test?
c. Determine H0 and Ha for this study.
d. Conduct the appropriate analysis. Should H0 be rejected? What should the researcher conclude?
e. Compute the 95 confidence interval.