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Use of True-Score Theory to Predict Moments of Univariate and Bivariate Observed-Score Distributions

Published online by Cambridge University Press:  01 January 2025

Frederic M. Lord*
Affiliation:
Educational Testing Service

Abstract

Formulas are derived for using the available item statistics and score statistics on a test to estimate the moments of the score distribution of a lengthened (or shortened) form of the same test. Other formulas are derived for estimating the bivariate moments of the scatterplot between two parallel test forms using only the data available on either form alone. An empirical study is made showing in each case satisfactory agreement between the theoretical values predicted from the formulas and the values actually observed. These results suggest the utility of the true-score model used in deriving the formulas.

Type
Original Paper
Copyright
Copyright © 1960 The Psychometric Society

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Footnotes

*

This work was supported by contract Nonr-2752(00) between the Office of Naval Research and Educational Testing Service. Reproduction in whole or in part for any purpose of the United States Government is permitted.

References

Cook, M. B. Bi-variatek-statistics and cumulants of their joint sampling distribution. Biometrika, 1951, 38, 179195.CrossRefGoogle ScholarPubMed
Hooke, R. Symmetric functions of a two-way array. Ann. math. Statist., 1956, 27, 5579.CrossRefGoogle Scholar
Kendall, M. G. The advanced theory of statistics (5th ed.), New York: Hafner, 1952.Google Scholar
Lord, F. M. Sampling fluctuations resulting from the sampling of test items. Psychometrika, 1955, 20, 122.CrossRefGoogle Scholar
Lord, F. M. Statistical inferences about true scores. Psychometrika, 1959, 24, 117.CrossRefGoogle Scholar
Lord, F. M. An approach to mental test theory. Psychometrika, 1959, 24, 283302.CrossRefGoogle Scholar
Lord, F. M. An empirical study of the normality and independence of errors of measurement in test scores. Psychometrika, 1960, 25, 91104.CrossRefGoogle Scholar