Exam 8: Interval Estimation

The sample size that guarantees the estimate of a population proportion satisfying the margin of error requirement is computed using a planning value of p equal to​

A random sample of 49 lunch customers was taken at a restaurant.The average amount of time these customers stayed in the restaurant was 45 minutes with a standard deviation of 14 minutes. a. Compute the standard error of the mean. b. With a .95 probability, what statement can be made about the size of the margin of error? c. Construct a 95% confidence interval for the true average amount of time customers spent in the restaurant. d. With a .95 probability, how large of a sample would have to be taken to provide a margin of error of 2.5 minutes or less?

The ability of an interval estimate to contain the value of the population parameter is described by the

In order to estimate the average electric usage per month, a sample of 64 houses was selected and the electric usage was determined.Assume a population standard deviation of 320 kilowatt-hours.If the sample mean is 1858 kWh, the 95% confidence interval estimate of the population mean is _____ kWh.