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Aide Scilab >> Statistiques > variance

variance

variance of the values of a vector or matrix

Calling Sequence

s=variance(x[,orien[,w]])
s=variance(x,'r') or m=variance(x,1)
s=variance(x,'c') or m=variance(x,2)

Arguments

x

real or complex vector or matrix

orien

the orientation of the computation. Valid values or the orien parameter are 1, "r", 2 and "c".

w

w : type of normalization to use. Valid values are 0 and 1. This depends on the number of columns of x (if orien = 1 is chosen), the number of rows (if orien = 2 is chosen). If w = 0, normalizes with m-1, provides the best unbiased estimator of the variance (this is the default). If w = 1, normalizes with m, this provides the second moment around the mean. If no orien option is given, the normalization is done with n * m - 1, where n * m is the total number of elements in the matrix.

Description

This function computes the variance of the values of a vector or matrix x.

For a vector or a matrix x, s=variance(x) returns in the scalar s the variance of all the entries of x.

s=variance(x,'r') (or, equivalently, s=variance(x,1)) is the rowwise variance. It returns in each entry of the row vector s the variance of each column of x. The generalized formulae is used, which manages complex values.

s=variance(x,'c') (or, equivalently, s=variance(x,2)) is the columnwise standard deviation. It returns in each entry of the column vector s the variance of each row of x. The generalized formulae is used, which manages complex values.

Examples

x=[0.2113249 0.0002211 0.6653811;0.7560439 0.4453586 0.6283918]
s=variance(x)
s=variance(x,'r')
s=variance(x,'c')

See Also

  • mtlb_var — Matlab var emulation function

Authors

Carlos Klimann

Bibliography

Wonacott, T.H. & Wonacott, R.J.; Introductory Statistics, fifth edition, J.Wiley & Sons, 1990.

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Last updated:
Wed Oct 05 12:10:58 CEST 2011