# 5. The Power of a Test

## d. explain a decision rule, the power of a test, and the relation between confidence intervals and hypothesis tests;

In hypothesis testing, what is Power? And how is it defined?
Power is the probability of correctly rejecting a false null hypothesis. Power is therefore defined as: `1 - β`

where `β`

is the Type II error probability.

What is the likely outcome if the power of an experiment is low? If the power of an experiment is low, then there is a good chance that the experiment will be inconclusive. That is why it is so important to consider power in the design of experiments.

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CFA

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