A client wants to determine whether there is a significant difference in the time required to complete a program evaluation with the three different methods that are in common use. Suppose the times (in hours) required for each of 18 evaluators to conduct a program evaluation follow.
Method 1 | Method 2 | Method 3 |
---|---|---|
68 | 64 | 58 |
72 | 73 | 65 |
69 | 79 | 66 |
77 | 68 | 55 |
75 | 74 | 56 |
74 | 70 | 64 |
Use α = 0.05 and test to see whether there is a significant difference in the time required by the three methods.
State the null and alternative hypotheses.
H0: Median1 ≠ Median2
≠ Median3
Ha: Median1 = Median2 =
Median3H0: Not all populations of
times are identical.
Ha: All populations of times are
identical. H0: All
populations of times are identical.
Ha: Not all populations of times are identical.
H0: Median1 = Median2 =
Median3
Ha: Median1 ≠ Median2 ≠
Median3H0: Median1 =
Median2 = Median3
Ha: Median1 > Median2
> Median3
Find the value of the test statistic. (Round your answer to two decimal places.)
Find the p-value. (Round your answer to three decimal places.)
p-value =
State your conclusion.
Reject H0. There is sufficient evidence to conclude that there is a significant difference in the time required by the three methods.
Reject H0. There is not sufficient evidence to conclude that there is a significant difference in the time required by the three methods.
Do not reject H0. There is not sufficient evidence to conclude that there is a significant difference in the time required by the three methods.
Do not reject H0. There is sufficient evidence to conclude that there is a significant difference in the time required by the three methods.
using excel>Addin>phstat>multiple sample test
we have
Kruskal-Wallis Rank Test for Differences in Medians | ||||||
Data | ||||||
Level of Significance | 0.05 | Group | Sample Size | Sum of Ranks | Mean Ranks | |
1 | 6 | 78 | 13 | |||
Intermediate Calculations | 2 | 6 | 69.5 | 11.5833333 | ||
Sum of Squared Ranks/Sample Size | 1911.083 | 3 | 6 | 23.5 | 3.91666667 | |
Sum of Sample Sizes | 18 | |||||
Number of Groups | 3 | |||||
Test Result | ||||||
H Test Statistic | 10.05556 | |||||
Critical Value | 5.991465 | |||||
p-Value | 0.006553 | |||||
Reject the null hypothesis |
State the null and alternative hypotheses.
H0: Median1 = Median2 = Median3
Ha: Median1 ≠ Median2 ≠ Median3
the value of the test statistic is 10.06
p-value =0.007
State your conclusion.
Reject H0. There is sufficient evidence to conclude that there is a significant difference in the time required by the three methods.
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