Which of the following statements is true?
A)The more variable the groups within a population are, the larger the sample needs to be to detect any real difference between the groups.
B)The more variable the groups within a population are, the smaller the sample needs to be to detect any real difference between the groups.
C)No matter how variable the groups within a population are, the size of the sample needed to detect a real difference between the groups is the same.
D)None of the above statements are true.

Question

Quizplus · Accepted Answer

When there is more variability within groups, it becomes more difficult to detect a significant difference between the groups because the variability increases the overlap between the groups. Therefore, to reduce the likelihood of making a Type II error (failing to detect a real difference between groups), a larger sample is needed to increase the power of the test.

Which of the Following Statements Is True