8.2 Suppose average pizza delivery times are normally distributed with an unknown population mean and a population standard deviation of six minutes. A random sample of 28 pizza delivery restaurants...

Extracted text: 8.2 Suppose average pizza delivery times are normally distributed with an unknown population mean and a population standard deviation of six minutes. A random sample of 28 pizza delivery restaurants is taken and has a sample mean delivery time of 36 minutes. Find a 90% confidence interval estimate for the population mean delivery time. Solution A Identify values to plug into the formula i + ( za (*)(-) Write solution first as x ± EBM: Write solution in interval notation: Solution B Check your "by hand" work by running a Zlnterval test: Interpretation