A polygraph (lie detector) is an instrument used to determine if the individual
ID: 3045609 • Letter: A
Question
A polygraph (lie detector) is an instrument used to determine if the individual is telling the truth. These tests are considered to be 92% reliable. In other words, if an individual lies, there is a 0.920 probability that the test will detect a lie. Let there also be a 0.080 probability that the test erroneously detects a lie even when the individual is actually telling the truth. Consider the null hypothesis, "the individual is telling the truth," to answer the following questions.
A polygraph (lie detector) is an instrument used to determine if the individual is telling the truth. These tests are considered to be 92% reliable. In other words, if an individual lies, there is a 0.920 probability that the test will detect a lie. Let there also be a 0.080 probability that the test erroneously detects a lie even when the individual is actually telling the truth. Consider the null hypothesis, "the individual is telling the truth," to answer the following questions.
Explanation / Answer
The null hypothesis (H0) statement is that the person is actually saying the truth
P (Type – I Error) =0.080
Thus the probability of Type I () error is 0.080
b)
Given that there is a 0.92 probability that a lie will be detected
P (Type – II Error) = , = 1 -
= 1 - 0.92
Thus P(Type II error) = 0.08