com.itemanalysis.psychometrics.irt.estimation

Class ItemResponseSimulator

java.lang.Object

com.itemanalysis.psychometrics.irt.estimation.ItemResponseSimulator

public class ItemResponseSimulator
extends java.lang.Object

ItemResponseSimulator.java creates data that contain item responses. This class supports all unidimensional item response models.

Constructor Summary

Constructors

Constructor and Description
ItemResponseSimulator(double[] theta, ItemResponseModel[] irm) Allows users to provide their own array of examinee ability values and item response models.
ItemResponseSimulator(int nPeople, ItemResponseModel[] irm) Allows users to specify the number of examinee ability parameters that will be drawn from a standrad normal distribution.

Method Summary

Modifier and Type	Method and Description
byte[][]	generateData() Creates a two-dimensional array of item responses.
void	generateData(java.lang.String outputFile, boolean includeID, boolean includeHeader) Generates a comma separated file (CSV file) of item responses.
void	generateData(java.lang.String path, java.lang.String baseName, boolean includeID, boolean includeHeader, int replications) Creates multiple CSV files of item response data.

Methods inherited from class java.lang.Object

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

Constructor Detail

ItemResponseSimulator

public ItemResponseSimulator(double[] theta,
                             ItemResponseModel[] irm)

Allows users to provide their own array of examinee ability values and item response models.

Parameters:

theta - an array of examinee ability parameters.

irm - an array of item response models.

ItemResponseSimulator

public ItemResponseSimulator(int nPeople,
                             ItemResponseModel[] irm)

Allows users to specify the number of examinee ability parameters that will be drawn from a standrad normal distribution. It also allows the user to provide the item response models.

Parameters:

nPeople - number of examinee ability parameter to create.

irm - an array of item response models.

Method Detail

generateData

public byte[][] generateData()

Creates a two-dimensional array of item responses.

Returns:

a two-dimensional array of item responses.

generateData

public void generateData(java.lang.String outputFile,
                         boolean includeID,
                         boolean includeHeader)
                  throws java.io.IOException

Generates a comma separated file (CSV file) of item responses.

Parameters:

outputFile - complete path and file name of output file

includeID - include an examinee ID number in the first column if true. Omits the ID if false.

includeHeader - if true will include variable names in first row of CSV file.

Throws:

java.io.IOException

generateData

public void generateData(java.lang.String path,
                         java.lang.String baseName,
                         boolean includeID,
                         boolean includeHeader,
                         int replications)
                  throws java.io.IOException

Creates multiple CSV files of item response data. Each file will have a unique names. For example, if path = "C:/mydata" and baseName = "itemdata" and replications = 2; the file names will be "C:/mydata/itemdata-rep1.csv" and "C:/mydata/itemdata-rep2.csv"

Parameters:

path - location where files will be stored

baseName - a base name for the CSV files. The will be appended to the path and a unique string will be added to the end.

includeID - include an examinee ID number in the first column if true. Omits the ID if false.

includeHeader - if true will include variable names in first row of CSV file.

replications - number of replications (and number of data files) to create

Throws:

java.io.IOException