2.3 Probability
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Question 31
The Venn diagram shows the probabilities associated with three events DDD, E E\,E and FFF, representing users of three social media apps. The probability of using only D D\,D is 0.1, only E E\,E is 0.35, and only F F\,F is 0.2. The intersection D∩E D \cap E\,D∩E is q q\,q and E∩F E \cap F\,E∩F is ppp. Events D D\,D and F F\,F have no common outcomes. The probability of using none of the apps is rrr.
a.[1]
Write down the two events that are mutually exclusive.
b.[2]
Given that P(E∣F)=0.2P(E | F) = 0.2P(E∣F)=0.2, find the value of ppp.
c.[4]
Given also that D D\,D and E E\,E are independent, find the values of q q\,q and rrr.
2.3 Probability Questions
200 exam-style questions on OCR (MEI) A Level Maths 2.3 Probability, covering 2.3.1 Calculate the probability of an event, 2.3.2 Complementary events, 2.3.3 Expected frequency of an event, 2.3.4 Diagrams to calculate probabilities, 2.3.5 Mutually exclusive and independent events, 2.3.6 Add probabilities for mutually exclusive events, 2.3.7 Multiply probabilities for independent events, 2.3.8 Mutually exclusive and independent events (notation) (A-level only), 2.3.9 Venn diagrams for probabilities (A-level only), 2.3.10 Conditional probabilities (A-level only), and 2.3.11 Independence via conditional probability (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.