@stdlib/stats
Version:
Standard library statistical functions.
70 lines (53 loc) • 1.36 kB
Plain Text
{{alias}}( x, k )
Evaluates the probability density function (PDF) for a chi-squared
distribution with degrees of freedom `k` at a value `x`.
If provided `NaN` as any argument, the function returns `NaN`.
If provided `k < 0`, the function returns `NaN`.
Parameters
----------
x: number
Input value.
k: number
Degrees of freedom.
Returns
-------
out: number
Evaluated PDF.
Examples
--------
> var y = {{alias}}( 0.3, 4.0 )
~0.065
> y = {{alias}}( 0.7, 0.7 )
~0.274
> y = {{alias}}( -1.0, 0.5 )
0.0
> y = {{alias}}( 0.0, NaN )
NaN
> y = {{alias}}( NaN, 2.0 )
NaN
// Negative degrees of freedom:
> y = {{alias}}( 2.0, -1.0 )
NaN
// Degenerate distribution when `k = 0`:
> y = {{alias}}( 2.0, 0.0, 2.0 )
0.0
> y = {{alias}}( 0.0, 0.0, 2.0 )
Infinity
{{alias}}.factory( k )
Returns a function for evaluating the probability density function (PDF) of
a chi-squared distribution with degrees of freedom `k`.
Parameters
----------
k: number
Degrees of freedom.
Returns
-------
pdf: Function
Probability density function (PDF).
Examples
--------
> var myPDF = {{alias}}.factory( 6.0 );
> var y = myPDF( 3.0 )
~0.126
See Also
--------