The STD function computes a sample standard deviation of data. The sample standard deviation of a column vector is computed as the square root of the sample variance. See the VAR function for details.
When x is a matrix, the sample variance is computed for each column, as the following example shows:
x = {5 1 10, 6 2 3, 6 8 ., 6 7 9, 7 2 13}; std = std(x); print std;
The STD function returns a missing value for columns with fewer than two nonmissing observations.