com.itemanalysis.psychometrics.reliability

Class AbstractScoreReliability

java.lang.Object

com.itemanalysis.psychometrics.reliability.AbstractScoreReliability

All Implemented Interfaces:

ScoreReliability, java.lang.Comparable<ScoreReliability>

Direct Known Subclasses:

CoefficientAlpha, FeldtBrennan, FeldtGilmer, GuttmanLambda, KR21, RajuBeta

public abstract class AbstractScoreReliability
extends java.lang.Object
implements ScoreReliability, java.lang.Comparable<ScoreReliability>

Methods implemented by all instances of ScoreReliability.

Field Summary

Fields

Modifier and Type	Field and Description
protected CovarianceMatrix	matrix
protected int	nItems

Constructor Summary

Constructors

Constructor and Description
AbstractScoreReliability()

Method Summary

Modifier and Type	Method and Description
int	compareTo(ScoreReliability that)
double[]	confidenceInterval() This confidence interval applies to Coefficient alpha because it has a known sampling distribution.
java.lang.String	confidenceIntervalToString(double[] confidenceInterval) Creates a String representation of the confidence interval.
boolean	equals(java.lang.Object obj)
int	hashCode()
double	totalVariance() Total observed score variance.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.itemanalysis.psychometrics.reliability.ScoreReliability

getType, itemDeletedReliability, printItemDeletedSummary, value

Field Detail

matrix

protected CovarianceMatrix matrix

nItems

protected int nItems

Constructor Detail

AbstractScoreReliability

public AbstractScoreReliability()

Method Detail

totalVariance

public double totalVariance()

Description copied from interface: ScoreReliability

Total observed score variance. It is the sum of all values in the covariance matrix.

Specified by:

totalVariance in interface ScoreReliability

Returns:

confidenceInterval

public double[] confidenceInterval()

This confidence interval applies to Coefficient alpha because it has a known sampling distribution. For other reliabilty methods it is only an approximation of the confidence interval because the sampling distribution of other reliability estimates is not known.

Specified by:

confidenceInterval in interface ScoreReliability

Returns:

confidence interval as an array with the lower bound in position 0 and the upper bound in position 1.

confidenceIntervalToString

public java.lang.String confidenceIntervalToString(double[] confidenceInterval)

Description copied from interface: ScoreReliability

Creates a String representation of the confidence interval. It is used for displaying results.

Specified by:

confidenceIntervalToString in interface ScoreReliability

Parameters:

confidenceInterval - an array with the lower [0] and upper [1] bounds of the confidence interval

Returns:

a String representation of the confidence interval.

compareTo

public int compareTo(ScoreReliability that)

Specified by:

compareTo in interface java.lang.Comparable<ScoreReliability>

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object