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PEDAR: Research Methodology Teaching Undergraduates in U.S. Postsecondary Institutions: Fall 1998
The 1999 National Study of Postsecondary Faculty
Study Sample
Accuracy of Estimtes
Data Analysis Systems
Statistical Procedures
Differences Between Means or Proportions
Linear Trends
Bivariate Correlations
Adjustments of Means to Control for Background Variation
Executive Summary
References
Full Report (PDF)
Executive Summary (PDF)
Statistical Procedures - Bivariate Correlations

For the bivariate correlations reported in the report, the strength of the relationships between pairs of variables was provided using a scale of magnitudes. Following Cohen (1988), reported magnitudes adopted the notion of a scale of small, moderate, and large sized relationships, qualitative terms that allow interpretation of the strength of a relationship through the concept of effect size. Cohen suggested that for a scale of the proportion of variance accounted for (the square of the correlation coefficient, r2), one might use a value of 0.01 to signify a small effect size, 0.09 for moderate, and 0.25 for large. Some latitude is appropriate in determining the scale of effect sizes within the context of the analysis. The magnitudes reported in this report were based on a scale in which the effect is small if r2 is less than 0.05, moderate if r2 is at least 0.05 but less than 0.25, and large if r2 is 0.25 or greater.


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