Formulas are provided for correcting point-biserial and biserial item-test correlations for the effect of chance success by guessing. It is pointed out that these chance-corrected correlations may sometimes exceed unity.
References
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Carroll, J. B. (1945), The effect of difficulty and chance success on correlations between items or between tests. Psychometrika, 10, 1-19.
2.
Carroll, J. B. (1961). The nature of the data, or how to choose a correlation coefficient. Psychometrika, 26, 347-372.
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Lord, F. M. , and Novick, M. R. (1968), Statistical theories of mental test scores. Reading, MA: Addison-Wesley.
