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Conditional Probability

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Question 69

An ecological survey analyzed 150 specific woodland plots to identify the presence of three rare fungal species: Amanita (AAA), Boletus (BBB), and Clitocybe (CCC). The findings were as follows:

  • 82 plots contained Amanita
  • 68 plots contained Boletus
  • 54 plots contained Clitocybe
  • 38 plots contained both Amanita and Boletus
  • 28 plots contained both Boletus and Clitocybe
  • 32 plots contained both Amanita and Clitocybe
  • 18 plots contained all three species
a.

Draw a Venn diagram to represent these data.

[4]
b.

Find the probability that a randomly selected plot from the survey:

contains none of these fungal species,

[1]
c.

contains Boletus but does not contain Amanita,

[2]
d.

contains at least two of these species.

[2]
e.

One plot is selected at random and is found to contain Amanita.

Find the probability that this plot also contains Boletus but does not contain Clitocybe.

[3]

Conditional Probability Questions

  1. A Level
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  3. /Conditional Probability