std (Statistics Toolbox)

std	Examples See Also

Standard deviation of a sample.

Syntax

y = std(X)

Description

std(X) computes the sample standard deviation of the data in X. For vectors, std(x) is the standard deviation of the elements in x. For matrices, std(X) is a row vector containing the standard deviation of each column of X.

std(X) normalizes by n-1 where n is the sequence length. For normally distributed data, the square of the standard deviation is the minimum variance unbiased estimator of

² (the second parameter).

The standard deviation is

where the sample average is

Examples

In each column, the expected value of y is one.

x = normrnd(0,1,100,6);
y = std(x)

y =

    0.9536    1.0628    1.0860    0.9927    0.9605    1.0254

y = std(-1:2:1)

y =

    1.4142