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The Upper and Lower Twenty-Seven Per Cent Rule

Published online by Cambridge University Press:  01 January 2025

Edward E. Cureton
Edward E. Cureton*
Affiliation:
University of Tennessee
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Abstract

A simplified re-derivation of the formula underlying the rule is presented, followed by a derivation of the comparable rule for the unitrectangular distribution, which turns out to be a 33-per cent rule. Critical comments are offered concerning two assumptions: normality of the score distribution and equality of mean standard errors of measurement in the high and low groups.

Type
Original Paper
Information
Psychometrika , Volume 22 , Issue 3 , September 1957 , pp. 293 - 296
Copyright
Copyright © 1957 The Psychometric Society

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References

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