Seasonal affective disorder (SAD) is a type of depression during seasons with less daylight (e.g., winter months).

Question:

Seasonal affective disorder (SAD) is a type of depression during seasons with less daylight (e.g., winter months). One therapy for SAD is phototherapy, which is increased exposure to light used to improve mood. A researcher tests this therapy by exposing a sample of SAD patients to different intensities of light (low, medium, high) in a light box, either in the morning or at night (these are the times thought to be most effective for light therapy). All participants rated their mood following this therapy on a scale from 1 (poor mood) to 9 (improved mood). The hypothetical results are given in the following table.

(a) Complete the F table and make a decision to retain or reject the null hypothesis for each hypothesis test.
(b) Compute Tukey's HSD to analyze the significant main effect. Summarize the results for this test using APA format.