In: Statistics and Probability
QUESTION 2
[25] After submitting your analysis, Chihiro noticed that the data she collected can be organized by the day of the week as can be seen in the following table.
Vancouver |
Saskatoon |
Montreal |
Halifax |
Sums |
Means |
|
Monday |
72 |
75 |
78 |
76 |
301 |
75.25 |
Tuesday |
74 |
77 |
77 |
73 |
301 |
75.25 |
Wednesday |
73 |
75 |
79 |
70 |
297 |
74.25 |
Thursday |
75 |
73 |
76 |
75 |
299 |
74.75 |
Friday |
68 |
67 |
72 |
65 |
272 |
68 |
Sums |
362 |
367 |
382 |
359 |
1470 |
|
Means |
72.4 |
73.4 |
76.4 |
71.8 |
∑ ?? =108,304 ?? ??
Suppose Chihiro asked you to reassess whether there are
differences in the mean productivities of the four locations but
this time taking into account the variability attributed to the day
of week.
(1) [1] Hypotheses
(2) [8] Compute the sum of squares for groups, blocks, and error by hand. (Show your calculations.) Complete the ANOVA table below.
Source of Variation SS df MS F p-value
Day (Block)
Location (main effect)
Error
Total
P-value
(3) [2] What will you say to Chihiro based on your results? Support your answer with the appropriate statistic.
(4) [2] How has blocking changed your conclusion of the hypothesis test here compared to your conclusion in the one-way ANOVA in question 1?
(5) [2] Is there evidence of significant differences between mean productivities for different days of week? Use the appropriate F-test to justify your answer.
(6) [10] If appropriate, use a post hoc test to determine where the significance differences lie by day of the week. Assume a significance level of 0.05. Interpret your results in context.