Use the following quiz questions to check your understanding of statistical power. Note that as soon as you have indicated your response, the question is scored and feedback is provided. As feedback is provided for each option, you may find it useful to try all of the responses (both correct and incorrect) to read the feedback, as a way to better understand the concept.

Understanding power

- Power is:
- The probability that the null hypothesis is true.
- That's not quite right. The null hypothesis is either true or false; there is no probability involved.

- The probability that the null hypothesis is false.
- That's not quite right. The null hypothesis is either true or false; there is no probability involved.

- The probability a false null hypothesis will be rejected.
- That's correct. Power relates to a study's ability to reject, correctly, a null hypothesis which is in fact false. A type II error is the failure to reject a false null hypothesis.

- The probability a true null hypothesis will be rejected.
- That's not quite right. The probability of rejecting a true null hypothesis is the probability of a type 1 error.

- If the power of a research study is low then
- The experiment will likely be inconclusive.
- That's correct. With low power, the null hypothesis is unlikely to be rejected. When the null hypothesis is not rejected, the experiment is inconclusive.

- Any significant findings obtained are suspect.
- That's not quite right. Significant findings are much less likely when power is low, but not out of the question.

- The results are skewed.
- That's not quite right. When a study has low power, the significance test is more likely to result in failing to reject the null hypothesis.

- Power is the probability of accepting the null hypothesis given that the null hypothesis is true.
- True
- That's not quite right. Remember that power is related to a type II error, which can only occur if the null hypothesis is false.

- False
- That's correct. Power is the probability of rejecting a false null hypothesis.

The following questions are multiple selection multiple choice. Choose all that apply to both questions before clicking on *Submit*.

## Acknowledgements

The questions included in this quiz were adapted from