During the calculation of any population standard deviation, the sum of the squared deviation is usually divided by N, which is the number of data entry in the population. Thereafter, the square root of the result would be taken.
On the other hand, during the calculation of the sample standard deviation, the sum of the squared deviations is usually divided by n - 1, with n being number of entries in the sample data set. Thereafter, the square root of the result would be taken.
