An educational psychologist would like to determine whether access to computers has an effect on grades for high school students. One group of n = 16 students has
home room each day in a computer classroom in which each student has a computer. A comparison group of n = 16 students has home room in a traditional
classroom. At the end of the school year, the average grade is recorded for each
student. The data are as follows:
Computer Traditional
M = 86 M = 82.5
SS = 1005 SS = 1155
a. Is there a significant difference between the two groups? Use a two-tailed test
with a = .05.
b. Compute Cohen's d to measure the size of the difference.
c. Write a sentence that demonstrates how the outcome of the hypothesis test and
the measure of effect size would appear in a research report.