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Maximum Likelihood Estimation of the Joint Covariance Matrix for Sections of Tests Given to Distinct Samples With Application to Test Equating

Thayer, Dorothy T.
Publication Year:
Report Number:
RR-82-14, PSRTR-82-29
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Correlation, Equated Scores, Maximum Likelihood Statistics, Statistical Analysis


Consider an old test X consisting of s sections and two new tests Y and Z similar to X consisting of p and q sections respectively. All subjects are given test X plus two variable sections from either test Y or Z. Different pairing of variable sections are given to each subsample of subjects. We present a method to estimate the covariance matrix of the combined test X(sub 1), X(sub s), Y(sub 1), Y(sub p), Z(sub 1), Z(sub q), and describe an application of these estimation techniques to linear, observed-score, test-equating. (20pp.)

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