THE BANK CUSTOMER WAITING TIME CASE: Wait Time Recall that a bank manager has developed a new system to reduce the time customers spend waiting to be served by tellers during peak business hours. The mean waiting time during peak business hours under the current system is roughly 9 to 10 minutes. The bank manager hopes that the new system will have a mean waiting time that is less than six minutes. The mean of the sample of 100 bank customer waiting times in Table 1.9 is 5.46. If we let μ denote the mean of all possible bank customer waiting times using the new system and assume that the population standard deviation equals 2.47: a) Calculate 95 percent and 99 percent confidence intervals for μ. Complete a confidence statement for the 95% using the following format: We are 95% confident the true population mean "write the context here" is between "write the interval here along with units.
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The margin of error is given by the formula: margin of error = critical value * (population standard deviation / sqrt(sample size) Given that the critical value for a 95% confidence interval is 1.96, the population standard deviation is 2.47, and the sample size Show more…
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Qudsiya A.
Recall that a bank manager has developed a new system to reduce the time customers spend waiting to be served by tellers during peak business hours. The mean waiting time during peak business hours under the current system is roughly 9 to 10 minutes. The bank manager hopes that the new system will have a mean waiting time that is less than six minutes. The mean of the sample of 102 bank customer waiting times is x¯x¯ = 5.47. If we let µ denote the mean of all possible bank customer waiting times using the new system and assume that σ equals 2.46: (a) Calculate 95 percent and 99 percent confidence intervals for µ. (Round your answers to 3 decimal places.) 95 percent confidence intervals for µ is [ , ]. 99 percent confidence intervals for µ is [ , ].
Maitreya E.
Waiting times (in hours) at a popular restaurant are believed to be approximately normally distributed with a variance of 2.25 during busy periods. a. A sample of 20 customers revealed a mean waiting time of 1.52 hours. Construct the $95 \%$ confidence interval for the population mean. b. Suppose that the mean of 1.52 hours had resulted from a sample of 32 customers. Find the $95 \%$ confidence interval. c. What effect does a larger sample size have on the confidence interval?
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