Fortynine items are randomly selected from a population of 5

Forty-nine items are randomly selected from a population of 500 items. The sample mean is 40 and the sample standard deviation 9.

Develop a 99 percent confidence interval for the population mean? (Round your answers to 3 decimal places.)

Solution

n =49

x bar =40

s = 9

std error =9/rt 49 = 1.286

Margin of error for 99%=2.58(1.286)

=3.3184

Confidence interval lower bound = Mean -3.3184 = 36.6816

Upper bound = 43.3184

The confidence interval is between 36.6816____    and_____43.3184