A polygraph (lie detector) is an instrument used to determine if the individual
ID: 3242977 • 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 95% reliable. In other words, if an individual lies, there is a 0.95 probability that the test will detect a lie. Let there also be a 0.005 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. What is the probability of Type I error? (Round your answer to 3 decimal places.) b. What is the probability of Type II error? (Round your answer to 2 decimal places.)Explanation / Answer
a) type I error =P(rejecting that person is telling the truth when he is telling the truth)
=0.005
b)probabilty of type II error =accepting that person is telling the truth when he is telling lie =1-0.95=0.05