Enter your data in a single column or row
Click an empty cell where you want the result
Type `=STDEV.S(range)` for a sample standard deviation
Type `=STDEV.P(range)` for a population standard deviation
Replace `range` with the cell range, such as `A1:A10`
Press Enter
Use `STDEV.S` for most data sets
Use `STDEV.P` only when your data includes the entire population