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2.3 Probability

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Question 112

In a study of genetically modified crop cultures, let R R\,R be the event that a culture exhibits rapid growth and S S\,S be the event that it shows stress resistance. Historical data suggests that:

P(R∩S)=0.12 P(R \cap S) = 0.12 P(R∩S)=0.12 P(R′∩S′)=0.28 P(R' \cap S') = 0.28 P(R′∩S′)=0.28 P(S)=2P(R) P(S) = 2P(R) P(S)=2P(R)
a.

Determine P(R)P(R)P(R).

[4]
b.

Find the probability that a culture shows stress resistance, given that it exhibits rapid growth.

[2]
c.

Determine, with a calculation, whether R R\,R and S S\,S are independent events.

[1]
Markscheme

2.3 Probability Questions

  1. A Level
  2. /Maths
  3. /2.3 Probability

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.

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