Posted by Jerry on .
Suppose the time it takes for a purchasing agent to complete an online ordering process is normally distributed with a mean of 8 minutes and a standard deviation of 2 minutes. Suppose a random sample of 25 ordering processes is selected.
The standard deviation of the sampling distribution of mean times is

Stats 
PsyDAG,
I think you are asking about the Standard Error of the mean (SEm).
SEm = SD/√n