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Confidence Interval of Automobile Shop Managers

An automobile shop manager timed six employees and found the average time it took then to change a water pump was 18 minutes. The standard deviation of the sample was 3 minutes. Find the 99% confidence interval of the true mean, and how would you explain the interval to the average layperson

Solution Preview

Please see the attached file.

Use the formula:
99% confidence interval for a given sample size, mean and standard deviation is:

Where is the mean = 18
σ is the standard deviation = 3
n is the sample size = 6
z0.005 = 2.576 is the ...

Solution Summary

The solution finds a 99% confidence interval of the true mean.