Author note — to cover (Higher)

Define P(A given B) by restricting attention to the trials where B happened, worked through counts and expected frequencies, with wording given that and of those who. Higher tier only. Exclude the algebraic formula dividing P(A and B) by P(B), and reversing conditions formally, both A level. Representations follow on three sibling pages. (P9)

• Fluency — direct questions on conditional probability, limited to this lesson's stated scope (4 questions).
• Application — use the same skill in unfamiliar or contextual questions without introducing a later method (4 questions).
• Check — questions built around the exclusions and likely misconceptions named in the lesson brief (4 questions).