IB skill practice

Use Bayes theorem and conditional probability

Apply conditional probability and Bayes theorem in structured probability contexts.

Paper 1, Paper 2 5 marks Difficulty 4

Use Bayes theorem and conditional probability - Bayes theorem and posterior probability item

Case A7. In weather model, \(P(storm)=0.28\), \(P(warning issued|storm)=0.88\), and \(P(warning issued|not storm)=0.08\). Calculate \(P(storm\mid warning issued)\), the numerical probability for storm day, and select the interpretation.

Worked practice: probability

Write the probability as a fraction or decimal, then interpret it if the question asks for a conclusion.