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WHAT SIZE SAMPLES FOR METHODS/MATERIALS EXPERIMENTS?
Author(s) -
FELDT LEONARD S.
Publication year - 1973
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.1745-3984.1973.tb00800.x
Subject(s) - sample size determination , stratified sampling , class size , statistics , simple random sample , mathematics , standardized test , class (philosophy) , mathematics education , psychology , computer science , medicine , artificial intelligence , environmental health , population
Careful planning of educational experiments includes decisions about the sample size to be used. This paper provides a guide to the minimum size of treatment groups, inferred from the relationships between pupil norms and norms for class averages of standardized achievement tests. With “highly effective” treatments and simple random assignment of subjects to conditions, 60 to 85 subjects is derived as the minimum number per group. With “moderately effective” treatments, the minimum number is 235 or more. Use of stratified samples reduces the minimum by fifteen to forty percent.