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

Question

Quizplus · Accepted Answer

The power of a test is the probability of correctly rejecting the null hypothesis when it is false (i.e. correctly identifying the person as a science student). To calculate the power, we need to know the probability of a Type II error (failing to reject the null hypothesis when it is false), which is equal to 1 - the probability of correctly identifying a science student. 
So, the probability of correctly identifying a science student is 1 - 0.16 = 0.84. Therefore, the power of the test is 0.84. 
The correct choice is C.

Instruction 9-2 a Student Claims That She Can Correctly Identify Whether a Whether