The Excel STDEVPA function calculates the standard deviation for an entire population. Unlike the STDEVP function, STDEVPA evaluates text and logicals that appear in references. To calculate standard deviation for a sample, use STDEVA or STDEV.S.
Get standard deviation for a population
Calculated standard deviation
=STDEVPA (number1, [number2], ...)
number1 - First number or reference in the sample.
number2 - [optional] Second number or reference.
The STDEVPA function calculates the standard deviation for data that represents an entire population, evaluating text and logicals as numbers as part of the calculation. TEXT is evaluated as zero, TRUE is evaluated as 1, and FALSE is evaluated as zero.
Standard deviation is a measure of how much variance there is in a set of numbers compared to the average (mean) of the numbers. The STDEVPA function is meant to estimate standard deviation for an entire population. If data represents a sample, use the STDEVA function.