Package edu.cmu.tetrad.util

Class CutoffFinder

java.lang.Object

edu.cmu.tetrad.util.CutoffFinder

public class CutoffFinder
extends Object

Provides a static method for finding the cutoff value for a symmetric probability distribution function about the origin.

Version:

$Id: $Id

Author:

josephramsey

Method Summary

Modifier and Type	Method	Description
static double	getCutoff(Function f, double xUpperBound, double alpha, double deltaX)	Assumes f is a positive symmetric function between x1 and x2 about 0.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

getCutoff

public static double getCutoff(Function f,
 double xUpperBound,
 double alpha,
 double deltaX)

Assumes f is a positive symmetric function between x1 and x2 about 0. Integrates from 0 in the direction of x2 in intervals of deltaX until an area of .5 * (1 - alpha) has been accumulated. Returns the x value at the iteration where this amount of area has been accumulated.

This is helpful for finding cutoff levels for normal curves, distributions of correlation coefficients, Student's t, etc. It returns significance level cutoffs.

Parameters:

f - a function

xUpperBound - an upper bound for the integration.

alpha - the significance level.

deltaX - the amount the integration jumps forward each time.

Returns:

the cutoff value for these conditions.