Back to: Chapter 6: Probability

5 thoughts on “Q4 | Bayes’ Theorem (Preview)

  1. Hi Jason!

    Is this included on the cheat sheet you have provided for ADMS 2320 students?

    Regards,
    Amitai

    1. I do not include Bayes’ formula. As I explain in the video, it is unnecessary and prone to error. The method I present here using the probability tree and the contingency table is a better method to make use of.

      Winter 2017 semester, the department no longer allows students to bring their own cheat sheets to ADMS 2320 exams. Instead, they will provide you with a department approved one when you write your exam. For this reason I no longer provide my pre-made cheatsheet downloads.
      Fall 2017 semester >> The department once again allows students to bring their own cheat sheets.
      1. I made that comment before even watching the video, sorry!

        By the way, absolutely love your resources and explanations. One of your videos has literally been more useful than attending a months worth of lectures. Thank you!

  2. Question 4 part c. Why is it P(B|P) and not P(P|B)?

    Thanking you in advance

    1. The question asks “What is the probability that the patient has a benign tumor…?” The rest is a condition – not a possible outcome. So we write the probability as:

      P(B occurring given the condition P). This is shortened to P(B|P).

      If we wrote it the other way around: P(P|B), that would mean we wanted to know the probability that P occurs given that the condition B). In other words, what is the chance that someone with a benign tumor receives a positive test – this is not what they asked.

      Please let me know if this helps!

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