A company's customer service department wants to compare the average service times at four different service locations. They want to conduct a hypothesis test to determine if all four means are the same or not. If n = 20 observations are taken at each of the four locations, then the degrees of freedom are D1 = 3 and D2 = 19.

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Quizplus · Accepted Answer

The degrees of freedom for the test statistic comparing the means are calculated as D1 = k - 1 for the numerator, where k is the number of groups (in this case, 4 service locations), so D1 = 4 - 1 = 3, which is correctly stated. However, for the denominator, the degrees of freedom are D2 = N - k, where N is the total number of observations across all groups and k is the number of groups. Since there are 20 observations taken at each of the four locations, N = 20 * 4 = 80. Therefore, D2 = 80 - 4 = 76, not 19.

A Company's Customer Service Department Wants to Compare the Average