If sigma is not known what can you use to estimate the standard deviation of xbar? What is this called?

sxbar=s/sqrt (n)

Standard error

Step-by-step explanation:

If population standard deviation is not known, then the sample estimate of standard deviation is used which is denoted by s. The standard deviation of the sample is calculated as an estimate. The population standard deviation of xbar is sigmabar which is computed as

σxbar=σ/sqrt (n)

If the population standard deviation is unknown, then standard deviation of xbar is computed as

sxbar=s/sqrt (n).

It is also known as standard error.