With sample mean x = 12.5, sample size n = 40 and population standard deviation = 4 find 99% confidence interval for population mean. use formula on page 312 with zα/2 = 2.575

The basic formula for estimating a confidence interval for a large sample is

Where is the parameter to be estimated.

is the point estimator of the parameter

is the standard error

and for this case is 2,575.

We estimate the average population, so:

is the estimator of

is the error.

Then the confidence interval is given by:

step-by-step explanation: