Chapter 9: Research Design Explained

You are now at the Chapter 9 section of the book's student Web site.

Here you can



Review and improve your understanding of the material Quiz yourself Apply this information Get help
See how the key terms are connected by looking at this concept map. Test yourself on the key terms with this matching test


Play this drag and drop matching game to see if you know your threats to internal validity.

Test yourself using flashcards.

If you have a fantasy baseball or football team, see how knowing about regression toward the mean can help you win.


Before investing, you should consider regression toward the mean.


Help with answering the end-of-chapter exercises.
Go through an online tutorial on internal validity


Go through our tutorial looking at the weaknesses of four designs.

Go through our murder mystery tutorial on internal validity (highly recommended!)


Review by

Take some practice quizzes
  • Short, general quiz
  • More specific quizzes
    • Take 12-item quizzes over the internal validity of  before-after designs and two-group designs (the first part of the chapter).
    • Take 8-item quizzes over the eight threats to internal validity (the second part of the chapter).
    • Take 7-item quizzes over random assignment and the tradeoffs between internal and external validity (the third part of the chapter).

  • Humorous example of making a wrong cause-effect conclusion ("The Onion" presents "proof" that Tommy is responsible for millions of divorces).

  • A researcher claims his study shows that vaping causes heart attacks, but does the study really show that?
  • Chapter 9 exercises


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