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