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Tests of Simple Slopes in Multiple Regression Models with an Interaction: Comparison of Four Approaches.
- Source :
-
Multivariate Behavioral Research . Jul/Aug2017, Vol. 52 Issue 4, p445-464. 20p. - Publication Year :
- 2017
-
Abstract
- In multiple regression researchers often follow up significant tests of the interaction between continuous predictors X and Z with tests of the simple slope of Y on X at different sample-estimated values of the moderator Z (e.g., ±1 SD from the mean of Z). We show analytically that when X and Z are randomly sampled from the population, the variance expression of the simple slope at sample-estimated values of Z differs from the traditional variance expression obtained when the values of X and Z are fixed. A simulation study using randomly sampled predictors compared four approaches: (a) the Aiken and West (1991) test of simple slopes at fixed population values of Z, (b) the Aiken and West test at sample-estimated values of Z, (c) a 95% percentile bootstrap confidence interval approach, and (d) a fully Bayesian approach with diffuse priors. The results showed that approach (b) led to inflated Type 1 error rates and 95% confidence intervals with inadequate coverage rates, whereas other approaches maintained acceptable Type 1 error rates and adequate coverage of confidence intervals. Approach (c) had asymmetric rejection rates at small sample sizes. We used an empirical data set to illustrate these approaches. [ABSTRACT FROM AUTHOR]
- Subjects :
- *MULTIPLE regression analysis
*SOCIOBIOLOGY
Subjects
Details
- Language :
- English
- ISSN :
- 00273171
- Volume :
- 52
- Issue :
- 4
- Database :
- Academic Search Index
- Journal :
- Multivariate Behavioral Research
- Publication Type :
- Academic Journal
- Accession number :
- 124882494
- Full Text :
- https://doi.org/10.1080/00273171.2017.1309261