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Tests of the Same Length Do Have the Same Standard Error of Measurement

Author(s):
Lord, Frederic M.
Publication Year:
1958
Report Number:
RB-58-07
Source:
ETS Research Bulletin
Document Type:
Report
Page Count:
15
Subject/Key Words:
Office of Naval Research, Error of Measurement, Test Length, Test Reliability

Abstract

For 50 tests whose mean scores were between 35 and 65 percent of the maximum possible score, the standard error of measurement, computed from actual data by a conventional formula, is found to correlate .996 with the square root of the number of items in the test.

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