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Conditional Probability

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Question 252

A botanical research station is studying a population of 200 rare plant specimens. The specimens are classified by their height, hhh cm, and their species type (Alpha or Beta), as shown in the table below.

Height, hhh cmSpecies AlphaSpecies Beta
h<15h < 15h<151832
15≤h<4015 \le h < 4015≤h<403545
40≤h40 \le h40≤h2743

One specimen is selected at random from the research station.

a.

Find the probability that the specimen is Species Alpha.

[2]
b.

Given that the specimen has a height of less than 15 cm, find the probability that it is Species Beta.

[2]
c.

Given that the specimen has a height of less than 40 cm, find the probability that it is Species Beta.

[3]
d.

State, with a reason, whether or not the event 'Species Beta' is independent of the event 'height is less than 15 cm'.

[2]
Markscheme

Conditional Probability Questions

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

368 exam-style questions on Edexcel A Level Maths Conditional Probability, covering 2.1 Set Notation, 2.2 Conditional Probability, 2.3 Conditional Probabilities in Venn Diagrams, 2.4 Probability Formulae, and 2.5 Tree Diagrams. Each one has a worked solution and a mark scheme showing where the marks go.

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