# Compute confidence interval and test population mean

1. Compute the 95% confidence interval on the population mean if a sample of 1000 is taken and the sample mean is found to be 15.95 and standard deviation is 4.2.

Interpret the interval. What does it mean?

2. Test to see if a population mean is greater than the assumed (or historical) value of 16. When a sample of 1000 was taken the sample mean was computed to be 15.95 and the sample standard deviation was 4.2.

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#### Solution Preview

1)

Z Value for 95% CI = 1.96

Upper CI = Mean + z * std dev / sqrt(n)

Lower CI = Mean - z * std dev / sqrt(n)

Upper CI = 15.95 + 1.96* 4.2 / SQRT(1000) = ...

#### Solution Summary

Provides steps necessary to compute the confidence interval and test population mean.

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