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.
Its source prints no answer for this problem, so there's nothing to check against.
OpenStax, Introductory Statistics 2e · §8.1 A Single Population Mean using the Normal Distribution · Exercise 9
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