1. Let Z be a standard normal random variable. Use the calculator provided, or this table, to determine the value of c such that
=P≤Zc0.7852
Carry your intermediate computations to at least four decimal places. Round your answer to two decimal places.
2. Alcohol withdrawal occurs when a person who uses alcohol excessively suddenly stops alcohol use. Studies have shown that the onset of withdrawal is experienced a mean of39.5 hours after the last drink, with a standard deviation of 19hours. A sample of 36people who use alcohol excessively is to be taken. What is the probability that the sample mean time between the last drink and the onset of withdrawal will be 37.3hours or more?
Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.
3. The workers’ union at a certain university is quite strong. About 94%of all workers employed by the university belong to the workers’ union. Recently, the workers went on strike, and now a local TV station plans to interview a sample of 20workers, chosen at random, to get their opinions on the strike.
A. Estimate the number of workers in the sample who are union members by giving the mean of the relevant distribution (that is, the expectation of the relevant random variable). Do not round your response.
B. Quantify the uncertainty of your estimate by giving the standard deviation of the distribution. Round your response to at least three decimal places.