Ackerman and Goldsmith (2011) found that students who studied text from printed hardcopy had better test scores than students who studied from text presented on a screen. In a related study, a professor noticed that several students in a large class had purchased the e-book version of the course textbook. For the final exam, the overall average for the entire class was m 5 81.7 but the n 5 9 students who used e-books had a mean of M 5 77.2 with a standard deviation of s 5 5.7.

a. Is the sample sufficient to conclude that scores for students using e-books were significantly different from scores for the regular class? Use a two-tailed test with a 5 .05.

b. Construct the 90% confidence interval to estimate the mean exam score if the entire population used e-books.

c. Write a sentence demonstrating how the results from the hypothesis test and the confidence interval would appear in a research report.