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| Achievement Gains | 1 |
| Comparative Analysis | 1 |
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| Pretests Posttests | 1 |
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| Journal of Experimental… | 1 |
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Peer reviewedWilliams, Richard H.; Zimmerman, Donald W. – Journal of Experimental Education, 1982
The reliability of simple difference scores is greater than, less than, or equal to that of residualized difference scores, depending on whether the correlation between pretest and posttest scores is greater than, less than, or equal to the ratio of the standard deviations of pretest and posttest scores. (Author)
Descriptors: Achievement Gains, Comparative Analysis, Correlation, Pretests Posttests
