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EVIDENCE ON THE QUALITY OF SEVERAL APPROXIMATIONS FOR COMMONLY USED MEASUREMENT STATISTICS 1
Author(s) -
McMORRIS ROBERT F.
Publication year - 1972
Publication title -
journal of educational measurement
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.917
H-Index - 47
eISSN - 1745-3984
pISSN - 0022-0655
DOI - 10.1111/j.1745-3984.1972.tb00766.x
Subject(s) - standard deviation , statistics , reliability (semiconductor) , consistency (knowledge bases) , mathematics , standard error , quality (philosophy) , internal consistency , psychometrics , discrete mathematics , physics , power (physics) , quantum mechanics
What is the extent of error likely with each of several approximations for the standard deviation, internal consistency reliability, and the standard error of measurement? To help answer this question, approximations were compared with exact statistics obtained on 85 different classroom tests constructed and administered by professors in a variety of fields; means and standard deviations of the resulting differences supported the use of approximations in practical situations. Results of this analysis (1) suggest a greater number of alternative formulas that might be employed, and (2) provide additional information concerning the accuracy of approximations with non‐normal distributions.