com.itemanalysis.psychometrics.measurement

Class ClassicalItemStatistics

java.lang.Object

com.itemanalysis.psychometrics.measurement.ClassicalItemStatistics

public class ClassicalItemStatistics
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
ClassicalItemStatistics(java.lang.Object id, boolean biasCorrection, boolean pearson)
ClassicalItemStatistics(java.lang.Object id, boolean biasCorrection, boolean pearson, boolean dIndex)

Method Summary

Modifier and Type	Method and Description
double	getDifficulty()
double	getDIndex()
double	getDindexLower()
double	getDindexUpper()
double	getDiscrimination()
java.lang.Object	getId()
double	getStdDev()
void	increment(double testScore, double itemScore) Incrementally update the item statistics
void	incrementDindex(double itemScore, double testScore, double lowCut, double upperCut) The D index must be incremented in a second loop after test scores have been computed and percentiles computed.
java.lang.String	toString() A string that contains all of the item statistics.

Methods inherited from class java.lang.Object

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

Constructor Detail

ClassicalItemStatistics

public ClassicalItemStatistics(java.lang.Object id,
                               boolean biasCorrection,
                               boolean pearson)

ClassicalItemStatistics

public ClassicalItemStatistics(java.lang.Object id,
                               boolean biasCorrection,
                               boolean pearson,
                               boolean dIndex)

Method Detail

increment

public void increment(double testScore,
                      double itemScore)

Incrementally update the item statistics

Parameters:

testScore - sum score on teh total test

itemScore - score on teh individual item (or response option)

incrementDindex

public void incrementDindex(double itemScore,
                            double testScore,
                            double lowCut,
                            double upperCut)

The D index must be incremented in a second loop after test scores have been computed and percentiles computed. Use this method to increment the D index.

Parameters:

itemScore - item response score

testScore - test summed score

lowCut - cutoff value for lower group

upperCut - cutoff value for the upper group

getId

public java.lang.Object getId()

Returns:

id of the response option

getDifficulty

public double getDifficulty()

getStdDev

public double getStdDev()

getDiscrimination

public double getDiscrimination()

getDindexLower

public double getDindexLower()

getDindexUpper

public double getDindexUpper()

getDIndex

public double getDIndex()

toString

public java.lang.String toString()

A string that contains all of the item statistics.

Overrides:

toString in class java.lang.Object

Returns:

string of estimated statistics