iews Discussion Discussion Course Materials iwo-Factor Analysis of variance (Ind
ID: 3220764 • Letter: I
Question
iews Discussion Discussion Course Materials iwo-Factor Analysis of variance (Independent Measures) aded Assignment Read Chapter 14 Back to Assignment Due Sunday 04.16.17 at 11:45 Attempts Average: 14 5. When to use a second factor Dr. Diane Gold and her colleagues study how rotating shift work (switching back and forth between the night shift and the day shift, for example) contributes to disrupted sleep cycles, accidents, and nodding Suppose are studying a group of nurses to see whether different circadian types are impacted differently by working particular types include larks, who are most active in the early morning; h who are active in the middle of the day; and owls, who are active late into the night. You administer a sleepiness test to 72 nurses (6 in each cell each day for a month and use an average score across the month for each person as the indication of each person's typical sleepiness. The means of the scores are shown in the following table, where a higher score indicates more sleepiness. Factor A: Factor B: Shift Rotation Circadian Day/Night/ Type Day/Evening Evening/Night Night/Day Evening M 0.17 M 0.33 M 0.50 M- 1.33 Mark -0.58 Lark Hummingbird M 1.50 M 0.50 M 0.33 M 0.17 Mumminatie 0.63 M 100 M 1.17 Owl M 1.33 M 1.67 Mont 1.29 Mo/E 1.00 MEN 0.61 MND 0.67 MowwVE 1.06 You perform a two-factor analysis of variance to test for an interaction effect between circadian type and work shifts. The following ANOVA summary table describes the results. SS df MS F Between treatments 20.3360 11 Factor A 7.5834 2 3.7917 5.74 Factor B 2.7778 3 0.9259 1.40 A X B interaction 9.9748 6 1.6625 2.51 Within treatments 39.6640 60 0.6611 Total 60.0000 71 Numerator Degrees of Freedom 16Explanation / Answer
A) Main effect due to factor A, F has 2 numerator(df of the factor) and 60 denominator(df of the within treatments) degrees of freedom.
F = 5.74
P(F2,60) = 0.005236 < 0.01
Therefore, Significant
Main effects due to factor B, F has 3 numerator and 60 denominator degrees of freedom.
F = 1.40
P(F3,60) = 0.2516 > 0.01
Therefore, Not significant
Interaction effects of the two factors, F has 6 numerator and 60 denominator degrees of freedom.
F = 2.51
P(F6,60) = 0.0311> 0.01
Therefore, Not significant
B) No, you should include circadian type as a second factor because there is a main effect for factor A and/or an interaction effect, meaning that including circadian type will likely reduce variance caused by individual differences.
A concern for single factor designs is the variance that exists within each treatment condition. Large variance tends to reduce the size of the F-ratio and reduces the likelihood of finding significant mean differences. Much of the variance comes from individual differences, here the individual differences being the different circadian types. This factor differs from individual to individual and can affect the scores obtained in the study
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.