Question

When does the standard error of the mean decrease?

Answer 1

To decrease standard error, we need to draw larger sample size.

Explanation:

Standard deviation of Sample mean or Standard error:

`SE = \sigma_{ \bar{x}} = \frac{\sigma}{\sqrt{n}}`

As we see, the standard error decreases if either population standard deviation is small (`\sigma`), or sample size is large (`n`). In general, we have no control over `\sigma`, so to decrease standard error, we need to increase the sample size (`n`)