IB DP Maths: AA HL復習筆記4.3.3 Bayes' Theorem

Category: IB課程, 教材筆記, 福利干貨 Date: 2022年7月13日上午10:52

Bayes' Theorem

What is Bayes’ Theorem

How do I calculate conditional probabilities using?Bayes’ Theorem?

Start by?drawing a tree diagram
- Label?B_1?&?B₂?(&?B₃?if necessary) on the?first set?of branches
- Label?A?&?A’?on the?second set?of branches
The questions will give you enough information to?label the probabilities?on this tree
Identify the probabilities needed?to use Bayes’ Theorem

Exam Tip

In an exam you are less likely to make a mistake when using the formula if you draw a tree diagram first

Worked Example

Lucy is doing a quiz. For each question there’s a 45% chance that it is about music, 30% chance that it is about TV and 25% chance that it is about literature. The probability that Lucy answers a question correctly is 0.6 for music, 0.95 for TV and 0.4 for literature.

a)? ? ? ?Draw a tree diagram to represent this information.

4-3-3-ib-aa-hl-bayes-theorem-a-we-solution