What is the difference between `STDEV.S` and `STDEV.P` in the context of SEM calculation?

`STDEV.S` calculates the sample standard deviation, which is appropriate for calculating the SEM when you're working with a sample from a larger population. `STDEV.P` calculates the population standard deviation, which is used when you have data for the entire population. Using `STDEV.P` would be incorrect for SEM calculation unless you truly have the entire population data.