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KR-21 for Formula Scored Tests With Omits Scored as Wrong

Author(s):
Boldt, Robert F.; Flaugher, Ronald L.; Linn, Robert L.; Rock, Donald A.
Publication Year:
1966
Report Number:
RB-66-40
Source:
ETS Research Bulletin
Document Type:
Report
Page Count:
10
Subject/Key Words:
Guessing (Tests), Kuder-Richardson Formulas, Mathematical Formulas, Scoring Formulas, Test Reliability

Abstract

An expression was derived for computing KR-21 based on formula score statistics for the special case when the number of items on the test equals the number right plus the number wrong (i.e., either there are no omits or omits are scored wrong). The effect of using means and variances based on formula scored tests in the KR-21 formula usually given in text- books was also discussed.

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