In addition to these more practical considerations, there is another factor that enters into our determination of the number of participants we will use. This factor is the amount of variability we expect to be present within each group. The less the within-group variability (i.e., the more homogeneous the participants), the fewer participants we will need. Conversely, the greater the within-group variability (i.e., the more heterogeneous the participants), the greater the number of participants we will need. (Smithg. The Psychologist as Detective: An Introduction to Conducting Research in Psychology, 5th Edition. Pearson Learning Solutions p. 128). <vbk:0558415520#outline(9.1.2)>