Statistical power

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Statistical power is definable in at least the following ways:

1. the likelihood that an inferential test will return a significant result based on a sample from a population in which there is a real effect.
2. the power of a statistical test is the probability that the test will reject the null hypothesis when the alternative hypothesis is true (i.e. that it will not make a Type II error).

Power can range between 0 and 1, with higher values indicating a greater likelihood of detecting an effect.

Contents 1 Increasing power 2 Power calculators 3 Data analysis exercises 4 See also

[edit] Increasing power

Power will be higher when:

1. the effect size is larger
2. the sample size is larger
3. the critical value is larger

[edit] Power calculators

Try searching using terms such as "statistical power calculator" and maybe also the type of test, and you should turn up links to useful pages such as:

1. One Sample Test Using Average Values
2. Post-hoc Statistical Power Calculator for Multiple Regression

[edit] Data analysis exercises

• Data analysis tutorial

[edit] See also

• Effect size