# Resolved: Sample Standard Error

In 4.2.+Population+variance+known,+z-score_exercise the solution to Standard Error uses the population standard deviation to calculate it. Isn't the standard error calculated with the sample's standard deviation?

Can you please clarify?

1 answers ( 1 marked as helpful)

Hi Wilson,

Please note that In this case, we know the population standard deviation. This is why we can use it.

Best,

Ned