2. (Section 8.1) LIGHT AT NIGHT MAKES FAT MICE: When Calories Are Consumed Studies have shown that exposure to light at night is harmful to human health. A study in mice shows that light at night has an effect on weight gain after just three weeks. In the study, mice were randomly assigned to live in one of three light conditions: LD had a standard light/dark cycle, LL had bright light all the time, and DM had dim light when there normally would have been darkness. Researchers hypothesized that the increased weight gain seen in mice with light at night might be caused by when the mice are eating. Perhaps mice with light at night eat a greater percentage of their food during the day, when they normally should be sleeping. Conditions for ANOVA are met and computer output for the percentage of food consumed during the day for each of the three light conditions is shown.

a. Make a formal statistical decision (Reject H0/Fail to reject H0) at the 1% level. b. Is there evidence that light at night influences when food is consumed by mice? c. Under what light conditions to mice eat the most food on average?

d. Can we conclude that there is a cause-and-effect relationship? e. State a conclusion in context that summarizes these answers.