MEAN

The MEAN function computes the mean of a numeric vector. MEAN calls the IDL function MOMENT.

Tip: You may want to use the RUNNING_STATS function instead, which avoids overflow for large values and also allows you to combine calculations for data sets that do not fit into memory.

Examples

; Define the n-element vector of sample data:

x = [65, 63, 67, 64, 68, 62, 70, 66, 68, 67, 69, 71, 66, 65, 70]

; Compute the average:

result = MEAN(x)

; Print the result:

PRINT, result

IDL prints:

66.7333

Syntax

Result = MEAN( X [, DIMENSION=value] [, /DOUBLE] [, /NAN] )

Return Value

Returns the average value of a set of numbers.

Arguments

X

An n-element, integer, double-precision or floating-point vector.

Keywords

DIMENSION

Set this keyword to a scalar indicating the dimension across which to calculate the mean. If this keyword is not present or is zero, then the mean is computed across all dimensions of the input array. If this keyword is present, then the mean is only calculated across a single dimension. In this case the result is an array with one less dimension than the input.

Note: If X only contains one element and DIMENSION=1, then MEAN returns a mean equal to X.

DOUBLE

If this keyword is set, computations are done in double precision arithmetic.

NAN

Set this keyword to cause the routine to check for occurrences of the IEEE floating-point values NaN or Infinity in the input data. Elements with the value NaN or Infinity are treated as missing data.

Version History

5.1	Introduced
8.0	Added DIMENSION keyword
9.0	Allow scalar input to work correctly with DIMENSION=1