The STANDARDDEVIATION function returns a numeric value that approximates the standard deviation of its arguments. The type
of this function is numeric.
Usage
FUNCTION STANDARDDEVIATION ({argument1} ... )
Parameter
argument1

Must be class numeric.

Returned Values
 The returned value is the approximation of the standard deviation of the
argument1 series.
 The returned value is calculated as follows:
1.

The difference between each
argument1 value and the arithmetic mean of the
argument1 series is calculated and squared.

2.

The values obtained are then added together. This quantity is divided by the number of values in the
argument1 series.

3.

The square root of the quotient obtained is then calculated. The returned value is the absolute value of the square root.

 If the
argument1 series consists of only one value, or if the
argument1 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.