Power and Type I and Type II Errors

When designing a study for which a statistical test will be carried out, the goal is usually to find evidence against the assumption about the theoretical world, as characterized by the null hypothesis. And if the study is well designed, there will be a high probability of rejecting the null hypothesis; this is the power of the test. This video considers the factors that affect the power, and the ways in which statistical tests can lead to incorrect conclusions.

Stream the video without the embedded quiz questions by clicking on the video link below. Closed captions are available.

Notes on the video: Power and Type I and Type II Errors

A point to consider for this video:

This video demonstrates how various values affect power for means using an applet to demonstrate statistical power. The applet was developed by the Web Interface for Statistics Education (WISE) project, but is unfortunately no longer supported by browsers. We are grateful to the WISE project for permission to use their applet.