Seasonal affective disorder (SAD) is a type of depression during seasons with le

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. (Round your answers to two decimal places. Assume experimentwise alpha equal to 0.05.)

Write a brief summary (only what is necessary) of the results for this test using APA format.

Note: DO NOT COPY AND PASTE SOMEONE ELSE'S SIMILAR QUESTION THAT WAS ANSWERED ON CHEGG. I have looked through all of them for over 40 minutes and NONE OF THE DATA MATCHES THE DATA I GAVE YOU HERE. I have had this done to me in the past. Please do not answer this unless you will answer it without copying another person's response. Thank you and God bless!

Explanation / Answer

By using MINITAB

a] General Linear Model: response versus time of day, Intensity

Factor Information

Factor Type Levels Values
time of day Fixed 2 1, 2
Intensity Fixed 3 1, 2, 3

Analysis of Variance

Source DF Adj SS Adj MS F-Value P-Value
time of day 1 0.6944 0.6944 0.32 0.576
Intensity 2 18.1667 9.0833 4.18 0.025
time of day*Intensity 2 0.7222 0.3611 0.17 0.848
Error 30 65.1667 2.1722
Total 35 84.7500

1] pvalue ( time of day ) = 0.576 > alpha = 0.05

Retain null hypothesis.

2] pvalue ( intensity ) = 0.025 < alpha = 0.05

reject null hypothesis.

3] pvalue ( inter1action effect ) =0.848 > alpha = 0.05

Retain null hypothesis.

b]

Tukey Pairwise Comparisons

Grouping Information Using the Tukey Method and 95% Confidence

Intensity N Mean Grouping
3 12 7.000 A
2 12 6.833 A B
1 12 5.417 B

Means that do not share a letter are significantly different.

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