In Chapter 12 (page 390), we described a study reporting that college students who are on Facebook

Question:

In Chapter 12 (page 390), we described a study reporting that college students who are on Facebook (or have it running in the background) while studying had lower grades than students who did not use the social network (Kirschner & Karpinski, 2010).
A researcher would like to know if the same result extends to students in lower grade levels. The researcher planned a two-factor study comparing Facebook users with non-users for middle school students, high school students, and college students.
For consistency across groups, grades were converted into six categories, numbered 0 to = from low to high. The results are presented in the following matrix.
a. Use a two-factor ANOVA with a = .05 to evaluate the mean differences.
b. Describe the pattern of results.