Some Practical Guidelines for Effective Sample-Size ...

Now we have all of the specifications needed for determining sample size using the power approach, and their values may be entered in suitable formulas, charts, or power-analysis software. Using the computer dialog shown in Figure 1, we find that a sample size of n = 23 per group is needed to achieve the stated goals. The actual power is .8049. The example shows how the pieces fit together ... ................
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