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Question 128

A screening test is used for a medical condition. It is known that 2% of the people who are screened have the condition.

If a person has the condition, the probability that the test is positive is 0.95.

If a person does not have the condition, the probability that the test is positive is 0.04.

a.

Find the probability that a randomly chosen person who is screened tests positive.

[2]
b.

Given that a person tests positive, find the probability that the person has the condition. Give your answer to 3 significant figures.

[3]
c.

State one assumption made in using the figure of 2% for the person being screened.

[1]
Markscheme

2 Statistics Questions

  1. A Level
  2. /Maths
  3. /2 Statistics

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