Videos: Part 2. Probability Revision and Bayes

This multimedia segment, Part 2. Probability Revision, includes four videos. Students are introduced to the implications of imperfect information, acquire a conceptual understanding of Bayes theorem, and gain practical skills in performing probability revision. In addition to the videos, materials include an instructor's note, companion slides, a glossary, an annotated bibliography, sample exercises, and additional support.

Students use the prior probability of water toxicity and the indices reflecting an imperfect test (e.g., sensitivity and specificity) to perform probability revision.  They calculate the posttest probability of water toxicity given a negative test result and the posttest probability of water toxicity given a positive test result.

Access the videos.

• Video 2.1 Probability revision using a flow chart (~9 min)
  In this video, students perform probability revision using an intuitive flow chart.
• Video 2.2 Probability revision using a 2 x 2 table (~8 min)
  In this video, students perform probability revision using a 2 x 2 table.
• Video 2.3 Probability revision using Bayes formula (~11 min)
  In this video, students perform probability revision using Bayes formula.
• Video 2.4 Probability revision using tree inversion (~20 min)
  In this video, students conduct probability revision using tree inversion. An alternative shorter (10 minutes) animation on probability revision using tree inversion is also available.

Multimedia segment Part 2. Probability Revision (Video 2.1, 2.2, 2.3, 2.4) was designed to follow Part 1. Testing the Water (Video 1.1, 1.2).

This teaching pack was developed by Sue J. Goldie at the Center for Health Decision Science, Harvard T.H. Chan School of Public Health. The multimedia components were developed as part of a series of pilots in the CHDS Media Hub, led by Jake Waxman, where media-based pedagogy experiments contribute to new ways of thinking about short form content.