Implications of inflexibility in the size of one sample for the statistical power of tests of mean contrasts
Article Abstract:
Factors beyond the control of researchers often limit the sizes of samples included in their studies. When these factors limit the total sample size, the statistical power of tests of contrasts of means may be unacceptably low. Sometimes these factors limit the size of only one sample (called the Fixed N sample), whose mean is to be contrasted with the mean of one other sample or with the average of the means of (g-1) other samples. In such situations, the upper bound for the statistical power of the contrast test may be much below the minimum power values conventionally considered acceptable, even though the total sample size could, in theory, be indefinitely large. Such unacceptably low powers occur not only for Cohen's (1988) small effects sizes but also for medium and large effect sizes when the fixed Ns are of magnitudes no smaller than the sample sizes often reported in psychological research. (Reprinted by permission of the publisher.)
Publication Name: Journal of Applied Behavioral Science
Subject: Social sciences
ISSN: 0021-8863
Year: 1990
User Contributions:
Comment about this article or add new information about this topic:
Using Cohen's tables to determine the maximum power attainable in two-sampletests when one sample is limited in size
Article Abstract:
Advantages of using equal sample sizes in 2 sample tests for means, correlations, and proportions are well known. However, in applied research there are frequently circumstances that limit the size of 1 of the 2 samples. This article draws attention to a simple method of determining, from Cohen's (1988) tables, the effects that this constraint (on the size of one sample) hason the maximum attainable power of these tests. These effects can be extremely serious in the case of small, medium, and even large effect sizes and clearly indicate that availability of a very large 2nd sample may not compensate for a constraint on the size of the 1st sample. (Reprinted by permission of the publisher.)
Publication Name: Journal of Applied Psychology
Subject: Social sciences
ISSN: 0021-9010
Year: 1993
User Contributions:
Comment about this article or add new information about this topic:
Some history of the Army General Classification Test
Article Abstract:
The United States military services desperately needed appropriate classification procedures when World War II started. The Army General Classification Test (AGCT), a mental ability test, was taken by more than 12,000,000 soldiers and marines to help the Army classify them for specialty and officer training. In 1940, prior to Pearl Harbor, the Personnel Research Section of the Adjutant General's Office in the War Department developed the AGCT. This article describes the efforts to produce the AGCT as well as interview procedures, trade tests, and aptitude tests for mechanical and clerical work. (Reprinted by permission of the publisher.)
Publication Name: Journal of Applied Psychology
Subject: Social sciences
ISSN: 0021-9010
Year: 1992
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Implications of computer-aided design for work and performance. Effects of intervention content and timing on group task performance
- Abstracts: Predictors of willingness to relocate for managerial and professional employees. Innovations and personal change: patterns of adjustment to relocation
- Abstracts: Homophobia: a weapon of sexism. Where are the children of the rainbow now? Sexual orientation education and homophobia reduction trainings
- Abstracts: Migration, return, and agricultural development in the Serra do Alvao, northern Portugal. part 2 Changing food prices and rural welfare: a nonparametric examination of the Cote d'Ivoire
- Abstracts: Determination of earnings in Yugoslav firms: can it be squared with labor management?