STDEV

Purpose:

Calculates the sample standard deviation of a series.

STDEV(series, first, points)

series	-	Optional. Any series or expression resulting in a series. Defaults to the current Window.
first	-	Optional. An integer, the first point to include in the calculation of the standard deviation. Defaults to 1.
points	-	Optional. An integer, the number of points to include in the standard deviation calculation. Defaults to the number of points from first to the end of the series.

A real.

stdev(gsin(100,0.01), 5, 20)

returns the standard deviation value 0.2403611.

stdev(W3, 5, 10)

returns the standard deviation of 10 points of the series in Window 3 starting with the 5th point.

STDEV computes the sample standard deviation defined as:

$image\std01.gif$

where the arithmetic mean is defined as:

$image\std02.gif$

STATS provides both STDEV and MEAN.

NaN values are ignored.

COLSTDEV can be used to determine the standard deviations of each column in a table.

See STD to calculate the population standard deviation.