Find the right sample size for your research in minutes and test the possible results before you begin your study, with IBM® SPSS® SamplePower. Strike the right balance among confidence level, statistical power, effect size, and sample size. Compare the effects of different study parameters with its flexible analytical tools. And, with an interactive guide and built-in help features, you won't lose time getting up to speed. This trial software expires after 14 days. The evaluation period begins on the date that you agree to the terms of the agreement.