please solve and show process Ex: Lie detectors, or polygraphs, are used to help
ID: 3365193 • Letter: P
Question
please solve and show process
Ex: Lie detectors, or polygraphs, are used to help determine whether a person has knowledge of a crime. These devices are based on autonomic changes in a person's nervous system. These tests typically involve answering a series of neutral questions among which a critical question is embedded. Psychological measurements in the form of skin responses are taken for each question. Suppose skin response scores are approximately normal with a mean of 49.40 and a standard deviation of 3.00. a) Suppose for the critical question, a suspect of a crime scores a 57.90. The probability that a suspect scores 57.90 or higher is: Answer: b) Suspects with skin response scores in the upper 3% are thought to have knowledge regarding the crime (lying). Find the minimum score that indicates lying. Answer:Explanation / Answer
Mean is 49.4 and s is 3. z is given as (x-mean)/s
a) P(x>57.9)= P(z>(57.9-49.4)/3)=P(z>2.83) or 1-P(z<2.83), from normal distribution table we get 1-0.9977=0.0023
b) for top 3%, the value at 1-0.03 or 97% has z value of 1.89
thus answer is mean+z*s= 49.4+1.89*3=55.07
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