|MATLAB Function Reference|
There are two common textbook definitions for the standard deviation
s of a data vector
and is the number of elements in the sample. The two forms of the equation differ only in versus in the divisor.
s = std(X),
X is a vector, returns the standard deviation using (1) above. If
X is a random sample of data from a normal distribution, is the best unbiased estimate of its variance.
X is a matrix,
std(X) returns a row vector containing the standard deviation of the elements of each column of
X is a multidimensional array,
std(X) is the standard deviation of th elements along the first nonsingleton dimension of
s = std(X,flag)
flag = 0, is the same as
flag = 1,
std(X,1) returns the standard deviation using (2) above, producing the second moment of the sample about its mean.
s = std(X,flag,dim)
computes the standard deviations along the dimension of
X specified by scalar