# D if the test result is statistically significant use

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d. If the test result is statistically significant, use Cohen’s d to estimate the effect size, given that the standard deviation, s p , equals 13.15.
=26.4-18.6/13.15 d=0.59 e. State how these test results might be reported in the literature, given s 1 =13.99 and s 2 =12.15.
15.7 An educational psychologist wants to check the claim that regular physical exercise improves academic achievement. To control for academic aptitude, pairs of college students with similar GPAs are randomly assigned to either treatment group that attends daily exercise classes or a control group. At the end of the experiment, the following GPAs are reported for the seven pairs of participants: GPAs Pair Numbers Physical Exercise (X 1 ) No Physical Exercise (X 2 ) 1 4.00 3.75 2 2.67 2.74 3 3.65 3.42 4 2.11 1.67 5 3.21 3.00 6 3.60 3.25 7 2.80 2.65 a. Using t, test the null hypothesis at the 0.01 level of significance.
b. Specify the p-value for this test result.
c. If appropriate (because the test result is statistically significant), use the Cohen’s d to estimate the effect size.
d. How might this test result be reported in literature?
15.8 A school psychologist wishes to determine whether a new antismoking film actually reduces the daily consumption of cigarettes by teenage smokers. The mean daily cigarette consumption is calculated for each of the eight teenage smokers during the month and the month after the film presentation, with the following results: Mean Daily Cigarette Consumption Smoker # Before Film (X 1 ) After Film (X 2 ) 1 28 26 2 29 27 3 31 32 4 44 44 5 35 35 6 20 16 7 50 47 8 25 23 (Note: When deciding on the form of the alternative hypothesis, H 1 , remember that a positive difference score (D=X 1 -X 2 ) reflects a decile in cigarette consumption.) a. Using t, test the null hypothesis at the 0.05 level of significance.