This utility calculates the sample size required to estimate a population mean with a specified level of confidence and precision.

Inputs are the assumed population standard deviation, the
desired level of confidence and the desired precision of the estimate.
The desired precision of the estimate (also sometimes called the allowable or
acceptable error in the estimate) is half the width of the desired
confidence interval. For example if you would like the confidence interval width to be about
2 kg (or whatever other units) you would enter a precision of +/- 1.

The program outputs the sample size required to estimate the true value with the desired precision and confidence.