Lecture video for “Data Sense: An Introduction to Statistics for the Behavioral Sciences” by Barton Poulson. This video covers Chapter 09: t-Tests, Section 03: The Repeated Measures t-Test. It explains how the t-test can be used to analyze changes in participants’ scores from time 1 to time 2, such as before and after an intervention. The book and complete set of videos may be purchased at http://kendallhunt.com/poulson/.