In: Statistics and Probability
a) The worksheet "EpisodeRatings" provides ratings of 3 TV shows by a total of 108 raters. The raters were randomly assigned to view 1 of 6 episodes of 3 TV shows. Raters filled out a questionnaire consisting of 10 items answered on scale from 1 to 15. The data on the Excel worksheet are average responses to the 10 questions by the raters. Each Episode-Show combination was rated by 6 people (6 replications of each factor combination). Run a two-way ANOVA with replication on this data using Excel's Data Analysis tools. Select all of the data (including labels) and specify 6 replications (rows per sample). What is the p-value of the hypothesis test on the "Episode" factor? Provide your answer with 4 decimal places.
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b) What is the average rating of the Show with the lowest mean rating? Provide your answer with 2 decimal places.
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c) What is the variance of the Episode-Show combination with the largest variability in ratings? Provide your answer with 4 decimal places.
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d) Based on the ANOVA test results, which of the Show means are significantly different at α = 5%?
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e) Three "effects" were tested in this two-way ANOVA. Order the 3 effects in terms of their usefulness in the ANOVA model for explaining the variation in mean ratings (start with the most useful effect).
Episode of Show Rated | Show A Rating | Show B Rating | Show C Rating |
Episode 1 | 10.1 | 10.7 | 10.6 |
9.8 | 10.7 | 10.6 | |
9.4 | 10.4 | 11.3 | |
9.2 | 10.4 | 9.6 | |
8.9 | 10 | 10 | |
9 | 9.9 | 9.4 | |
Episode 2 | 9.7 | 10.5 | 10.4 |
9.6 | 9.8 | 11.1 | |
9.6 | 9.6 | 11.9 | |
9.2 | 9.5 | 9.3 | |
8.8 | 9.8 | 10.1 | |
9.2 | 9.7 | 9.7 | |
Episode 3 | 9.3 | 9.5 | 9.5 |
10.1 | 9.4 | 9.9 | |
9.8 | 9.9 | 9.4 | |
9 | 10.3 | 9.4 | |
8.7 | 10.4 | 10.1 | |
8.8 | 9.9 | 9.8 | |
Episode 4 | 9.8 | 10.8 | 11 |
10.7 | 10.1 | 10.8 | |
10.8 | 9.4 | 11 | |
9 | 10.1 | 9.4 | |
9.7 | 9.5 | 9 | |
8.9 | 10 | 9.4 | |
Episode 5 | 9.2 | 10.8 | 9.7 |
9.3 | 10.3 | 10.5 | |
9.9 | 10.6 | 11.2 | |
10.7 | 10.6 | 9.6 | |
11.5 | 10.8 | 10 | |
11.3 | 11.2 | 9.6 | |
Episode 6 | 10 | 10.2 | 9.7 |
9.7 | 10.6 | 9.4 | |
9.9 | 11.2 | 8.7 | |
9.6 | 10.2 | 9.4 | |
9.2 | 11 | 9.4 | |
9.7 | 11.6 | 8.9 |
excel steps for two way anova with replication
excel>menu>data>data analysis>two way anova with replication>enter required label
Anova: Two-Factor With Replication | ||||||
SUMMARY | Show A Rating | Show B Rating | Show C Rating | Total | ||
Episode 1 | ||||||
Count | 6 | 6 | 6 | 18 | ||
Sum | 56.4 | 62.1 | 61.5 | 180 | ||
Average | 9.4 | 10.35 | 10.25 | 10 | ||
Variance | 0.22 | 0.115 | 0.511 | 0.441176471 | ||
Episode 2 | ||||||
Count | 6 | 6 | 6 | 18 | ||
Sum | 56.1 | 58.9 | 62.5 | 177.5 | ||
Average | 9.35 | 9.816666667 | 10.41666667 | 9.861111111 | ||
Variance | 0.119 | 0.125666667 | 0.905666667 | 0.540163399 | ||
Episode 3 | ||||||
Count | 6 | 6 | 6 | 18 | ||
Sum | 55.7 | 59.4 | 58.1 | 173.2 | ||
Average | 9.283333333 | 9.9 | 9.683333333 | 9.622222222 | ||
Variance | 0.317666667 | 0.164 | 0.085666667 | 0.235947712 | ||
Episode 4 | ||||||
Count | 6 | 6 | 6 | 18 | ||
Sum | 58.9 | 59.9 | 60.6 | 179.4 | ||
Average | 9.816666667 | 9.983333333 | 10.1 | 9.966666667 | ||
Variance | 0.653666667 | 0.253666667 | 0.86 | 0.534117647 | ||
Episode 5 | ||||||
Count | 6 | 6 | 6 | 18 | ||
Sum | 61.9 | 64.3 | 60.6 | 186.8 | ||
Average | 10.31666667 | 10.71666667 | 10.1 | 10.37777778 | ||
Variance | 0.993666667 | 0.089666667 | 0.408 | 0.507712418 | ||
Episode 6 | ||||||
Count | 6 | 6 | 6 | 18 | ||
Sum | 58.1 | 64.8 | 55.5 | 178.4 | ||
Average | 9.683333333 | 10.8 | 9.25 | 9.911111111 | ||
Variance | 0.077666667 | 0.32 | 0.139 | 0.609281046 | ||
Total | ||||||
Count | 36 | 36 | 36 | |||
Sum | 347.1 | 369.4 | 358.8 | |||
Average | 9.641666667 | 10.26111111 | 9.966666667 | |||
Variance | 0.4705 | 0.308730159 | 0.572 | |||
ANOVA | ||||||
Source of Variation | SS | df | MS | F | P-value | F crit |
Sample | 5.442685185 | 5 | 1.088537037 | 3.081249672 | 0.01297146 | 2.315689238 |
Columns | 6.912407407 | 2 | 3.456203704 | 9.783246842 | 0.000143026 | 3.097698035 |
Interaction | 10.05537037 | 10 | 1.005537037 | 2.846307071 | 0.004027979 | 1.937566791 |
Within | 31.795 | 90 | 0.353277778 | |||
Total | 54.20546296 | 107 |
p-value of the hypothesis test on the "Episode" factor=0.0130
average rating of the Show with the lowest mean rating=9.64
the variance of the Episode-Show combination with the largest variability in ratings=0.5720