Chapter 15.1, Problem 7E

Do people feel hungrier after sampling a healthy food? The authors of the paper “When Healthy Food Makes You Hungry” (Journal of Consumer Research [2010]: S34–S44) carried out a study to answer this question. They randomly assigned volunteers into one of three groups. The people in the first group were asked to taste a snack that was described as a new health bar containing high levels of protein, vitamins, and fiber. The people in the second group were asked to taste the same snack, but were told it was a tasty chocolate bar with a raspberry center. After tasting the snack, participants were asked to rate their hunger level on a scale from 1 (not at all hungry) to 7 (very hungry). The people in the third group were asked to rate their hunger but were not given a snack.

The data in the accompanying table are consistent with summary quantities given in the paper (although the sample sizes in the actual study were larger).

1. a. Do these data provide evidence that the mean hunger rating is not the same for all three treatments (“healthy” snack, “tasty” snack, no snack)? Test the relevant hypotheses using a significance level of 0.05.
2. b. Is it reasonable to conclude that the mean hunger rating is greater for people who do not get a snack? Explain.