Standardized z-scores
returns
the z-score for
each element of Z
= zscore(X
)X
such that columns of X
are
centered to have mean 0 and scaled to have standard deviation 1. Z
is
the same size as X
.
If X
is a vector, then Z
is
a vector of z-scores.
If X
is a matrix, then Z
is
a matrix of the same size as X
, and each column
of Z
has mean 0 and standard deviation 1.
For multidimensional arrays, z-scores
in Z
are computed along the first
nonsingleton dimension of X
.
scales Z
= zscore(X
,flag
)X
using
the standard deviation indicated by flag
.
If flag
is 0 (default), then zscore
scales X
using
the sample standard deviation, with n -
1 in the denominator of the standard deviation formula. zscore(X,0)
is
the same as zscore(X)
.
If flag
is 1, then zscore
scales X
using
the population standard deviation,
with n in the denominator of standard deviation
formula.
zscore
returns NaN
s for
any sample containing NaN
s.
zscore
returns 0
s for any sample that is constant (all
values are the same). For example, if X
is a vector of the same numeric
value, then Z
is a vector of 0
s.