A Single Population Mean using the Normal Distribution · Exercise 9
The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau surveys 200 people. The sample mean is 8.2 minutes. There is a known standard deviation of 2.2 minutes. The population distribution is assumed to be normal.
Construct a 90% confidence interval for the population mean time to complete the forms. State the confidence interval, sketch the graph, and calculate the error bound.
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OpenStax, Introductory Statistics 2e · §8.1 A Single Population Mean using the Normal Distribution · Exercise 9
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