This calculator helps you find the appropriate sample size for estimating the mean of a population that’s normally distributed within a specified margin of error.

You need to provide the confidence interval, the margin of error, and the population standard deviation (σ) below and click the ‘Calculate’ button:

Assuming the population standard deviation to be 10, you need a sample size of:

**171**

to estimate a mean with 95% confidence and a precision of 1.5

The confidence interval is usually 90%, 95%, or 99%.

The formula to calculate the sample size is:

`n = (Z`_{α/2}σ/E)^{2}

Where `n`

is the sample size,
`Z`

is the z critical value, _{α/2}`E`

is the margin of error, and σ is the population standard deviation.

I hope this calculator is useful. Happy analyzing!