Variance (GenericNamedArraylist function)

Calculate variance of items or function of items (FloatNamedArraylist, NamedArraylist, and UnicodeNamedArraylist classes)

[Introduced in Sirius Mods 7.8]

This method returns by default the variance of the values of the items in the collection, or it returns the variance of the items after a specified function has been applied to them.

The variance is the "mean standard deviation" of the values of the items in the collection, the average of the squares of the deviations of the value of each item from the mean of all the items.

Syntax

%number = anyNal:Variance[( [itemFunction])]

Syntax terms

%number	A Float variable to contain the numeric result.
anyNal	An FloatNamedArraylist, NamedArraylist, or UnicodeNamedArraylist object.
itemFunction	A function that operates on the type of the items in the collection. It may be a local method or method variable or a class member (Variable, Property), and it must return an intrinsic (probably Float) value. The default itemFunction value is the special identity function, This, which simply returns the item value.

Examples

b %nl is namedarrayList of float %nl = new %nl('April') = 3000 %nl('May') = 5000 %nl('June') = 8000 print %nl:variance end

The result is:

4222222.22222222

See also

Arraylist class FloatNamedArraylist class NamedArraylist class UnicodeNamedArraylist class	List of Arraylist methods List of FloatNamedArraylist methods List of NamedArraylist methods List of UnicodeNamedArraylist methods List of Collection methods	Arraylist methods syntax FloatNamedArraylist methods syntax NamedArraylist methods syntax UnicodeNamedArraylist methods syntax
Notation conventions for methods