The STANDARD-DEVIATION function returns a numeric value that approximates the standard deviation of its arguments. The type
of this function is numeric.

- Argument-1 must be class numeric.

- The returned value is the approximation of the standard deviation of the argument-1 series.
- The returned value is calculated as follows:
- The difference between each argument-1 value and the arithmetic mean of the argument-1 series is calculated and squared.
- The values obtained are added. This quantity is divided by the number of values in the argument-1 series.
- The square root of the quotient obtained is calculated. The returned value is the absolute value of this square root.

- If the argument-1 series consists of only one value, or if the argument-1 series consists of all variable occurrence data items and the total number of occurrences for all of them is one, the returned value is zero.
- Floating-point format is used for numeric non-integer results.