com.itemanalysis.psychometrics.polycor

Class PolychoricTwoStep

java.lang.Object

com.itemanalysis.psychometrics.polycor.AbstractPolychoricCorrelation

com.itemanalysis.psychometrics.polycor.PolychoricTwoStep

All Implemented Interfaces:

PolychoricCorrelation

Direct Known Subclasses:

PolychoricMaximumLikelihood

public class PolychoricTwoStep
extends AbstractPolychoricCorrelation

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	PolychoricTwoStep.TwoStepLikelihoodFunction Likelihood function for the two-step approximation.

Field Summary

Fields inherited from class com.itemanalysis.psychometrics.polycor.AbstractPolychoricCorrelation

columnThresholds, data, fmin, incremental, N, ncol, norm, nrow, rho, rowThresholds, table

Constructor Summary

Constructors

Constructor and Description
PolychoricTwoStep() Constructor for incrementally updating the data.
PolychoricTwoStep(double[][] data) Constructor for use when data have been summarized in an row x column frequency table.
PolychoricTwoStep(TwoWayTable table) Constructor for use when data have been summarized in a TwoWayTable.

Method Summary

Modifier and Type	Method and Description
java.lang.String	print()
double	value() Two-step estimate of the polychoric correlation.

Methods inherited from class com.itemanalysis.psychometrics.polycor.AbstractPolychoricCorrelation

cumulativeColumnSums, cumulativeRowSums, extractColumnThresholds, extractRho, extractRowThresholds, getColumnThresholds, getParameterArray, getRowThresholds, increment, increment, increment, initialize, logLikelihood

Methods inherited from class java.lang.Object

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

Constructor Detail

PolychoricTwoStep

public PolychoricTwoStep(double[][] data)

Constructor for use when data have been summarized in an row x column frequency table.

Parameters:

data - a row by column table of frequencies.

PolychoricTwoStep

public PolychoricTwoStep(TwoWayTable table)

Constructor for use when data have been summarized in a TwoWayTable.

Parameters:

table - a TwoWayTable.

PolychoricTwoStep

public PolychoricTwoStep()

Constructor for incrementally updating the data. Must call increment(x, y) to add data to object before calling value().

Method Detail

value

public double value()

Two-step estimate of the polychoric correlation.

Returns:

a correlation

print

public java.lang.String print()