TABLE 9-2
A student claims that he can correctly identify whether a person is a business major or an agriculture major by the way the person dresses. Suppose in actuality that if someone is a business major, he can correctly identify that person as a business major 87% of the time. When a person is an agriculture major, the student will incorrectly identify that person as a business major 16% of the time. Presented with one person and asked to identify the major of this person (who is either a business or agriculture major), he considers this to be a hypothesis test with the null hypothesis being that the person is a business major and the alternative that the person is an agriculture major.
-Referring to Table 9-2, what is the power of the test?
A) 0.87
B) 0.16
C) 0.13
D) 0.84

Question

Quizplus · Accepted Answer

Power of the test is the probability of correctly rejecting the null hypothesis when it is false. In this case, the null hypothesis is that the person is a business major and the alternative hypothesis is that the person is an agriculture major. 
The probability of correctly identifying an agriculture major is 1 - 0.16 = 0.84. Therefore, the power of the test is 0.84. So, the best choice is D.

TABLE 9-2 a Student Claims That He Can Correctly Identify Whether a Whether