The number of years employed was determined for a sample of employees at a large company.

The following MINITAB output presents a confidence interval for the population mean length of employment.

a. Fill in the blanks: We are _______________ confident that the population mean number of years employed is between _____________________ and ______________ .

b. Use the appropriate critical value along with the information in the computer output to construct a 95% confidence interval.

c. Find the sample size needed so that the 98% confidence interval will have a margin of error of 1.0.

d. Find the sample size needed so that the 95% confidence interval will have a margin of error of 1.0.

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The assumed sigma = 8.0000 Variable X N Mean 58 2.657 SE Mean 98% CI 1.0505 (0.1233, 5.1007)