Most statistical tests rely upon certain assumptions
about the variables used in the analysis. When these
assumptions are not met the results may not be
trustworthy, resulting in a Type I or Type II error, or
over- or under-estimation of significance or effect
size(s). As Pedhazur (1997, p. 33) notes,
"Knowledge and understanding of the situations
when violations of assumptions lead to serious
biases, and when they are of little consequence, are
essential to meaningful data analysis". However, as
Osborne, Christensen, and Gunter (2001) observe,
few articles report having tested assumptions of the
statistical tests they rely on for drawing their
conclusions. This creates a situation where we have
a rich literature in education and social science, but
we are forced to call into question the validity of
many of these results, conclusions, and assertions, as
we have no idea whether the assumptions of the
statistical tests were met. Our goal for this paper is to
present a discussion of the assumptions of multiple
regression tailored toward the practicing researcher