com.itemanalysis.psychometrics.irt.estimation

Class ItemParamPriorNormal

java.lang.Object

com.itemanalysis.psychometrics.irt.estimation.ItemParamPriorNormal

All Implemented Interfaces:

ItemParamPrior

public class ItemParamPriorNormal
extends java.lang.Object
implements ItemParamPrior

Implementation of an ItemParamPrior for the Normal distribution. This class is a translation of ItemParamPriorNormal.cpp in Brad Hanson's ETIRM library, Copyright (c) 2000, Bradley A. Hanson.

Constructor Summary

Constructors

Constructor and Description
ItemParamPriorNormal() Constructor for the standard normal distribution
ItemParamPriorNormal(double[] parameters) A constructor for an array of parameters.
ItemParamPriorNormal(double mean, double sd)

Method Summary

Modifier and Type	Method and Description
java.lang.String	distributionName()
int	getNumberOfParameters()
double	logDensity(double p) Only compute part of the log of the density that depends on the parameter
double	logDensityDeriv1(double p) First derivative of log density.
double	logDensityDeriv2(double p)
double	nearestNonZero(double x) Empty method
boolean	zeroDensity(double p) Empty method

Methods inherited from class java.lang.Object

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

Constructor Detail

ItemParamPriorNormal

public ItemParamPriorNormal()

Constructor for the standard normal distribution

ItemParamPriorNormal

public ItemParamPriorNormal(double[] parameters)

A constructor for an array of parameters. The first element must be the mean and the second element must be the standard deviation.

Parameters:

parameters - parameters for the normal distribution

ItemParamPriorNormal

public ItemParamPriorNormal(double mean,
                            double sd)

Method Detail

logDensity

public double logDensity(double p)

Only compute part of the log of the density that depends on the parameter

Specified by:

logDensity in interface ItemParamPrior

Parameters:

p - Argument of log density function (an item parameter value)

Returns:

logDensityDeriv1

public double logDensityDeriv1(double p)

First derivative of log density. Only compute part of the log of the density that depends on the parameter

Specified by:

logDensityDeriv1 in interface ItemParamPrior

Parameters:

p -

Returns:

logDensityDeriv2

public double logDensityDeriv2(double p)

Specified by:

logDensityDeriv2 in interface ItemParamPrior

getNumberOfParameters

public int getNumberOfParameters()

Specified by:

getNumberOfParameters in interface ItemParamPrior

distributionName

public java.lang.String distributionName()

Specified by:

distributionName in interface ItemParamPrior

zeroDensity

public boolean zeroDensity(double p)

Empty method

Specified by:

zeroDensity in interface ItemParamPrior

Parameters:

p -

Returns:

nearestNonZero

public double nearestNonZero(double x)

Empty method

Specified by:

nearestNonZero in interface ItemParamPrior

Parameters:

x -

Returns: