If we run six independent comparisons among means, each at the five percent level, the overall familywise error rate will be approximately
A) .05.
B) .05/6.
C) .30.
D) .01.

Question

Quizplus · Accepted Answer

The overall familywise error rate for multiple comparisons can be approximated using the formula 1 - (1 - α)^n, where α is the significance level for each individual test and n is the number of tests. Using α = 0.05 and n = 6, the calculation is 1 - (1 - 0.05)^6 ≈ 0.265, which is approximately 0.30. This represents the probability of making at least one Type I error across all comparisons.

If We Run Six Independent Comparisons Among Means, Each at the Five