What is your desired margin of error?

%

The margin of error is the measure of how precise your estimate will be. A lower margin of error will require a larger sample size because this means that you desire higher precision. IPMVP suggests you strive for 10%.

What confidence level do you need?

%

The confidence level is how certain you are that an estimate will fall within your desired precision range. A higher confidence level will require a larger sample size. Typically IPMVP requires 90%.

What is the population size?

The population size is the total number of items you would measure if you had to measure all of them. For example, if you had 1,000 fixtures to calculate savings for at a confidence level of 90% and a margin of error of 10%, you would measure 64 fixtures. 1,000 fixtures is your population and 64 fixtures is your sample size.