One Way to Increase Power Is to Minimize the Variability

Multiple Choice

One way to increase power is to minimize the variability of the raw scores.How might this be accomplished?

A) Change  from 0.05 to 0.01.
B) Change the size of N from 100 to 25.
C) Design and conduct the experiment so that all the subjects in a sample are treated in a consistent manner.
D) Select two very different levels of the independent variable that are likely to produce a relatively large difference between the means.