Standard deviation
Syntax: | s = STDEV(x) s = STDEV(w,x) |
The STDEV
function only accepts one or two vector arguments.
If only one vector is entered, the function returns the standard deviation of that vector's data. If two
vectors are entered, the first vector holds the weights and the second vector holds the data. The result is
always a scalar value.
Suppose that x is a vector with N elements.
A weight vector, w, may be entered as the first argument. The
length of w is assumed to also be N. If no weights are entered,
defaults to
1
, for .
Define the total weight:
The mean value, , is
defined by
The variance, , is
defined by
The standard deviation, ,
is defined by
Examples
Suppose X = [1;2;3;4;5;6;7;8;9;10]
, then A = STDEV(X)
returns
scalar A
with the value 3.02765
.
Suppose W = [1;1;1;5;5;5;5;1;1;1]
, then A = STDEV(W,X)
returns
scalar A
with the value 2.09293
.