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ERIC Number: ED173367
Record Type: RIE
Publication Date: 1978-Mar-30
Reference Count: 0
The Use of Analysis of Covariance in Tests of Attribute-by-Treatment Interactions.
Delaney, Harold D.; Maxwell, Scott E.
Analysis of covariance is examined for its usefulness in attribute-by-treatment interaction (ATI) research, where subjects are randomly assigned to treatments but not to levels of the attribute factor. Contrary to what might be expected, the use of a covariate does not confound the interpretation of the interaction between attribute and treatment, because the expected value of the interaction effect is independent of the particular covariate chosen. Independence occurs regardless of whether the attribute variable is discrete or continuous, and regardless of whether the covariate is measured with perfect or less than perfect reliability. The primary implication of these results is that analysis of covariance provides a much needed means for researchers to achieve powerful designs in assessing attribute-by-treatment interactions. (Author/GDC)
Publication Type: Speeches/Meeting Papers; Reports - Research
Education Level: N/A
Authoring Institution: N/A
Note: Paper presented at the Annual Meeting of the American Educational Research Association (62nd, Toronto, Ontario, Canada, March 27-31, 1978)