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Back to 8.1 A Confidence Interval When the Population Standard Deviation Is Known or Large Sample Size

8.1 Exercise 2

Avg difficulty 2.5

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.

OpenStax Introductory Business Statistics 2e, 8.1 A Confidence Interval When the Population Standard Deviation Is Known or Large Sample Size, exercise 2

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Adapted from Introductory Business Statistics 2e © 2023 Rice University. Licensed under CC BY 4.0. Source: Introductory Business Statistics 2e. Imported at revision 50ec917.