## Sample size required to estimate means

Sample Size to estimate means | ||
---|---|---|

Confidence Level ($1-\alpha$) | ||

Standard Deviation ($\sigma$) | ||

Margin of Error ($E$) | ||

Results | ||

Z value: | ||

Required Sample Size : ($n$) | ||

## Sample size required to estimate difference between means of independent samples

The formula to estimate the sample size required to estimate the mean of two independent samples is

`$$ n_i =2\bigg(\frac{z\sigma}{E}\bigg)^2; i=1,2 $$`

where

- $n_i$ is the sample size for $i^{th}$ group,
- $z$ is the $Z_{\alpha/2}$,
- $\sigma$ is the population standard deviation and
- $E$ is the margin of error.