Calculates the sample or population standard deviation of a series.
STD(series, mode, dim)
series 
 
Optional. Any series or expression resulting in a series. Defaults to the current Window.  
mode 
 
Optional. An integer,
the normalization mode. For
 
dim 
 
Optional. An integer, the summation dimension.

A real scalar for a one column series or a 1xM real table for an M column series.
W1: 1..10
std(W1)
returns 3.0277 the sample standard deviation.
W1: 1..10
std(W1 + 1e7)
Returns 3.0277, same as above since the true standard deviation is independent of the mean value.
W1: 1..10
std(W1, 1)
Returns 2.8723, the population standard deviation.
W1: ravel(1..9, 3)^2
W2: std(W1, 0)
W3: std(W1, 0, 2)
W1 == {{1, 16, 49}
{4, 25, 64},
{9, 36, 81}}
W2 == {{4.0415, 10.0167, 16.0104}}
W3 == {24.5561,
30.4467,
36.3731}
W2 computes the standard deviation of each column of W1 and W3 computes the standard deviation of each row of W1.
For a series of length N, the basic form of the
sample standard deviation
where the arithmetic mean is defined as:
The population standard deviation
STD uses a fast, highly accurate running sums algorithm that exhibits insensitivity to roundoff errors.
As shown in the second example, the standard deviation is independent of an additive mean value.
NaN values are ignored.
STD returns the standard deviation of each column for a multicolumn series. See STDEV to return the standard deviation of a multicolumn series as a whole.