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2.5.3 Hypothesis test for a Normal mean (A-level only)

2.5.3 Hypothesis test for a Normal mean (A-level only)

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Question 23

A call centre claims that the amount of time a worker spends on each phone call can be modelled by a normal distribution with a mean of 8 minutes and a standard deviation of 2 minutes.

a.

Using this model, find the probability that the time the worker spends on a randomly selected phone call is more than 11 minutes.

[1]
b.

The call centre manager thinks that the mean time for each phone call is more than 8 minutes. The manager takes a random sample of 20 phone calls and finds that the average time is 8.8 minutes. Test the manager's belief at the 5% significance level. You should state your hypotheses clearly.

[4]
Markscheme

2.5.3 Hypothesis test for a Normal mean (A-level only) Questions

  1. A Level
  2. /Maths
  3. /2.5.3 Hypothesis test for a Normal mean (A-level only)

130 exam-style questions on AQA A Level Maths 2.5.3 Hypothesis test for a Normal mean (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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