Journals Information
Universal Journal of Psychology(CEASE PUBLICATION) Vol. 1(2), pp. 21 - 31
DOI: 10.13189/ujp.2013.010201
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Modern Robust Statistical Methods: Basics with Illustrations Using Psychobiological Data
Rand R. Wilcox1,*, Douglas A. Granger2, Florence Clark3
1 Dept. of Psychology, University of Southern California, Los Angeles, CA 90089-1061, United States
2 Center for Interdisciplinary Salivary Bioscience Research, Johns Hopkins University, School of Nursing, Bloomberg School of Public Health, and School of Medicine
3 Division of Occupational Science & Occupational Therapy, University of Southern California
ABSTRACT
Psychological studies in general, and psychobiological studies in particular, routinely use a collection of classic statistical techniques aimed at comparing groups or studying associations. A fundamental issue is whether violating the basic assumptions underlying these methods, namely normality and homoscedasticity, can result in relatively poor power or miss important features of the data that have practical significance. In the statistics literature, hundreds of papers make it clear that under general conditions the answer is yes and that routinely used strategies for dealing with violations of assumptions can be unsatisfactory. Moreover, a vast array of new and improved techniques is now available for dealing with violations of assumptions, including more flexible methods for dealing with curvature. The paper reviews the major insights regarding standard methods, explains why some seemingly reasonable methods for dealing with violations of assumptions are technically unsound, and then outlines methods that are technically correct. It then illustrates the practical importance of modern methods using data from the Well Elderly II study.
KEYWORDS
Psychobiological studies, robust statistical methods, outliers, curvature, heteroscedasticity, smoothers, biomarkers, depressive symptoms, meaningful activity
Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Rand R. Wilcox , Douglas A. Granger , Florence Clark , "Modern Robust Statistical Methods: Basics with Illustrations Using Psychobiological Data," Universal Journal of Psychology(CEASE PUBLICATION), Vol. 1, No. 2, pp. 21 - 31, 2013. DOI: 10.13189/ujp.2013.010201.
(b). APA Format:
Rand R. Wilcox , Douglas A. Granger , Florence Clark (2013). Modern Robust Statistical Methods: Basics with Illustrations Using Psychobiological Data. Universal Journal of Psychology(CEASE PUBLICATION), 1(2), 21 - 31. DOI: 10.13189/ujp.2013.010201.