*40*

The sample size required to estimate a population mean with a certain level of confidence and a desired margin of error is calculated as:

Sample size =(z

_{α/2}σ/E)^{2}where:

- z
_{α/2}: The z critical value - E: The desired margin of error
- σ: The population standard deviation

To find the sample size required to estimate a population mean, simply fill in the boxes below and then click the “Calculate” button.

**Sample Size: ** 35