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CBSE Class 12 Maths

Probability

Each concept is a short lesson, then questions until you get three right.

0/4

4 concepts, a short lesson each

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Conditional probability

P(A∣B)=P(A∩B)P(B)P(A \mid B) = \frac{P(A \cap B)}{P(B)}: BB has happened, so BB is the new sample space

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Rules0 of 4

  1. Conditional probabilityP(A∣B)=P(A∩B)P(B)P(A \mid B) = \frac{P(A \cap B)}{P(B)}: BB has happened, so BB is the new sample spaceStart
  2. The multiplication theoremP(A∩B)=P(A) P(B∣A)P(A \cap B) = P(A)\,P(B \mid A): draws without replacement change the second probabilityStart
  3. Independent eventsP(A∩B)=P(A) P(B)P(A \cap B) = P(A)\,P(B); "at least one" =1−P(none)= 1 - P(\text{none})Start
  4. Total probability and Bayes' theoremP(Ei∣A)=P(Ei)P(A∣Ei)∑jP(Ej)P(A∣Ej)P(E_i \mid A) = \frac{P(E_i)P(A \mid E_i)}{\sum_j P(E_j)P(A \mid E_j)}: work backwards from the resultStart

Practise Probability

Once the concepts click, try the questions your exam asks.