public class Studentst
extends java.lang.Object
Modifier | Constructor and Description |
---|---|
protected |
Studentst()
Make class non-instantiable but inheritable.
|
public static double t(double t, double df) throws java.lang.IllegalArgumentException
t
- Percentage point of Student t distributiondf
- Degrees of freedomjava.lang.IllegalArgumentException
- if df <= 0
The probability is computed using the following relationship between the incomplete beta distribution and Student's t:
tprob(t) = incompleteBeta( df/(df*t*t), df/2, 0.5 )
The result is accurate to about 14 decimal digits.
public static double tInverse(double p, double df) throws java.lang.ArithmeticException, java.lang.IllegalArgumentException
p
- Probability level for percentage pointdf
- Degrees of freedomjava.lang.IllegalArgumentException
- p < 0 or p > 1 or df <= 0java.lang.ArithmeticException
- if incomplete beta evaluation fails
The percentage point is computed using the inverse incomplete beta distribution. This allows for fractional degrees of freedom.