# Question: At a department store catalog orders counter the average time

At a department store catalog orders counter, the average time that a customer has to wait before being served has been found to be approximately exponentially distributed, with a mean (and standard deviation) of 3.5 minutes. For a simple random sample of 36 recent customers, invoke the central limit theorem and determine the probability that their average waiting time was at least 4.0 minutes.

**View Solution:**## Answer to relevant Questions

It has been reported that the average U.S. teenager sends 80 text messages per day. For purposes of this exercise, we will assume the daily number of text messages sent is normally distributed with a standard deviation of ...A simple random sample with n = 300 is drawn from a binomial process in which π = 0.4. Determine the following probabilities for p = the proportion of successes: a. P(p ≥ 0.35) b. P(0.38 ≤ p ≤ 0.42) c. P(p ≤ 0.45) According to the Federal Trade Commission (FTC), about 3.4% of items come up at the wrong price when scanned at the retail checkout counter. Freda Thompson, director of investigations for her state’s consumer affairs ...For a population of five individuals, television ownership is as follows: a. Determine the probability distribution for the discrete random variable, x = number of television sets owned. Calculate the population mean and ...For a given sample size, the standard error of the sample mean is 10 grams. With other factors unchanged, to what extent must the sample size be increased if the standard error of the sample mean is to be just 5 grams?Post your question