Managerial statistics

Chapter 8 (Sampling Distribution) 1. A normal population has a mean of 60 and a standard deviation of 12. You select a random sample of 9. Required a. Compute the standard error of the mean b. Find the probability that the sample mean is greater than 63 c. Find the probability that the sample mean is less than 56 d. Find the probability that the sample mean is between 56 and 63 2. You conducted research and found that employees at a manufacturing facility extend their lunch break by eight (8) minutes. Suppose the extended break follows a normal distribution with a standard deviation of 4.75. For a sample of 16 randomly selected employees. Required a. Find the probability that the extended break is more than six (6) minutes. b. If the company is seeking to discourage extended lunch break practice among employees, what would you recommend? Chapter 9 (Confidence Intervals) 1. Assume a simple random sample of 36 items is selected from a population with a standard deviation of 5. Assume the sample mean is 25. Required a. What is the standard error of the mean? b. At 90% confidence interval, calculate the margin of error c. Determine the 90% confidence interval for the population mean. 2. What is the sample size required to estimate a population mean to within 2 units given that the population standard deviation is 10? Use a confidence level of 95%. 1