# Question: A polygraph lie detector is an instrument used to determine

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?

b. What is the probability of Type II error?

c. Discuss the consequences of Type I and Type II errors.

d. What is wrong with the statement, “I can prove that the individual is telling the truth on the basis of the polygraph result.”

a. What is the probability of Type I error?

b. What is the probability of Type II error?

c. Discuss the consequences of Type I and Type II errors.

d. What is wrong with the statement, “I can prove that the individual is telling the truth on the basis of the polygraph result.”

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