std
Standard deviation
Syntax
Description
returns the standard
deviation of the elements of S
= std(A
)A
along the first array dimension
whose size does not equal 1. By default, the standard deviation is normalized by
N-1
, where N
is the number of
observations.
If
A
is a vector of observations, thenS
is a scalar.If
A
is a matrix whose columns are random variables and whose rows are observations, thenS
is a row vector containing the standard deviation corresponding to each column.If
A
is a multidimensional array, thenstd(A)
operates along the first array dimension whose size does not equal 1, treating the elements as vectors. The size ofS
in this dimension becomes1
while the sizes of all other dimensions are the same asA
.If
A
is a scalar, thenS
is0
.If
A
is a0
-by-0
empty array, thenS
isNaN
.
specifies a weighting scheme. When S
= std(A
,w
)w = 0
(default), the standard
deviation is normalized by N-1
, where N
is the
number of observations. When w = 1
, the standard deviation is
normalized by the number of observations. w
also can be a weight
vector containing nonnegative elements. In this case, the length of
w
must equal the length of the dimension over which
std
is operating.
computes the standard deviation over the dimensions specified in the vector
S
= std(A
,w
,vecdim
)vecdim
when w
is 0 or 1. For example, if
A
is a matrix, then std(A,0,[1 2])
computes the standard deviation over all elements in A
, since
every element of a matrix is contained in the array slice defined by dimensions 1
and 2.
[
also returns the mean of the elements of S
,M
] = std(___)A
used to calculate the
standard deviation. If S
is the weighted
standard deviation, then M
is the weighted
mean. This syntax is valid for MATLAB versions R2022a and later.