ILE COBOL Language Reference


STANDARD-DEVIATION

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

The function type is numeric.

Format
 
                                   .------------.
                                   V            |
>>-FUNCTION STANDARD-DEVIATION--(----argument-1-+--)-----------><
 
 
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:

  1. The difference between each argument-1 and the arithmetic mean of the argument-1 series is calculated and squared.
  2. The values obtained are then added together. This quantity is divided by the number of values in the argument-1 series.
  3. The square root of the quotient obtained is then 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.

The equivalent arithmetic expression for FUNCTION STANDARD-DEVIATION is:

FUNCTION SQRT (FUNCTION VARIANCE (argument-1))

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