A fourth-grade teacher suspects that the time she administers a test, and what sort of snack her students have before the test, affects their performance. To test her theory, she assigns 90 fourth-grade students to one of three groups. One group gets candy (a lollipop) for their 9:55 AM snack. Another group gets a high-protein snack (beef ) for their 9:55 AM snack. The third group does not get a 9:55 AM snack. The teacher also randomly assigns 10 of the students in each snack group to take the test at three different times: 10:00 AM (right after snack), 11:00 AM (an hour after snack), and 12:00 PM (right before lunch).
Suppose that the teacher uses a two-factor independent-measures ANOVA to analyze these data. Without post hoc tests, which of the following questions can be answered by this analysis? (Note: Assume that receiving no snack is considered one type of snack.) Check all that apply.
Is there a difference among the scores for the test times because fourth graders are more alert in the morning?
Does the effect of the timing of the test depend on the type of snack the students eat?
Do students who are tested at 12:00 PM score lower than students who are tested at 10:00 AM?
Do students who eat a candy snack score higher than students who have a protein snack?