edu.northwestern.at.utils.math.distributions

## Class FishersF

• java.lang.Object
• edu.northwestern.at.utils.math.distributions.FishersF

• ```public class FishersF
extends java.lang.Object```
Fisher's F distribution functions.
• ### Constructor Summary

Constructors
Modifier Constructor and Description
`protected ` `FishersF()`
Make class non-instantiable but inheritable.
• ### Method Summary

Methods
Modifier and Type Method and Description
`static double` ```f(double f, double dfn, double dfd)```
Compute probability for Fisher's F distribution.
`static double` ```fInverse(double p, double dfn, double dfd)```
Compute percentage point for Fisher's F distribution.
• ### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`
• ### Constructor Detail

• #### FishersF

`protected FishersF()`
Make class non-instantiable but inheritable.
• ### Method Detail

• #### f

```public static double f(double f,
double dfn,
double dfd)
throws java.lang.IllegalArgumentException```
Compute probability for Fisher's F distribution.
Parameters:
`f` - Percentage point of Fisher's F distribution
`dfn` - Numerator degrees of freedom
`dfd` - Denominator degrees of freedom
Returns:
The corresponding probabiity for Fisher's F distribution.
Throws:
`java.lang.IllegalArgumentException` - if dfn <= 0 or dfd <= 0 .

fprob(f) = incompleteBeta( dfd/(dfd*f*dfn), df/2, dfn/2 )

The result is accurate to about 14 decimal digits.

• #### fInverse

```public static double fInverse(double p,
double dfn,
double dfd)
throws java.lang.IllegalArgumentException```
Compute percentage point for Fisher's F distribution.
Parameters:
`p` - Probability level for percentage point.
`dfn` - Numerator degrees of freedom.
`dfd` - Denominator degrees of freedom.
Returns:
The corresponding probabiity for Fisher's F distribution.
Throws:
`java.lang.IllegalArgumentException` - if p < 0 or p > 1 or dfn <= 0 or dfd <= 0 .
`java.lang.ArithmeticException` - if incomplete beta evaluation fails