ABSTRACT
In Chapter 4, you learned how to test individual comparisons among means and assess their practical significance through such procedures as confidence intervals and effect size measures. You were also introduced to the concepts oflinear independence and orthogonality. As these two concepts demonstrate, several contrasts are often tested on the same set of data. Linear independence and orthogonality concern the degree of overlap in information obtained from testing several contrasts among a groups. In this chapter, another issue that arises in testing several contrasts is considered. We will approach this issue primarily from the perspective of hypothesis testing, but we will see that the issue is also relevant for confidence intervals.
