Which of the following is an example of cluster sampling? a) A sample of 351 people called a radio show to express their opinions about the verdict in a criminal trial. b) In order to assess students' satisfaction with the food establishments on campus, the first 50 students who came out of the student center were interviewed. c) A poll asked a random sample of 1,112 adults whether they believe that the use of recreational marijuana should be legalized nationwide. d) A health educator wanted to study the sleeping habits of the undergraduate students in her university. For her study, the researcher chose a simple random sample of size 150 from each of the classes (150 freshmen, 150 sophomores, 150 juniors, and 150 seniors), for a total of 600 sampled students. e) The human resources department of a large bank wanted to assess the job satisfaction of the bank's workers. The department chose four of the bank's branches at random, and used all of the workers in those four Screenshot

The head of maintenance at XYZ Rent-A-Car believes that the mean number of miles between services is 3290 miles, with a standard deviation of 384 miles. If he is correct, what is the probability that the mean of a sample of 33 cars would be less than 3160 miles? Round your answer to four decimal places.

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