MATLAB Function Reference

var

Variance

Syntax

• var(X)
  var(X,1)
  var(X,w)
  

Description

var(X) returns the variance of X for vectors. For matrices, var(X)is a row vector containing the variance of each column of X. var(X) normalizes by N-1 where N is the sequence length. This makes var(X) the best unbiased estimate of the variance if X is a sample from a normal distribution.

var(X,1) normalizes by N and produces the second moment of the sample about its mean.

var(X,W) computes the variance using the weight vector W. The number of elements in W must equal the number of rows in X unless W = 1, which is treated as a short-cut for a vector of ones. The elements of W must be positive. var normalizes W by dividing each element in W by the sum of all its elements.

The variance is the square of the standard deviation (STD).

See Also

corrcoef, cov, std

vander

varargin, varargout