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2.5.8 Hypothesis test for a single mean (A-level only)

2.5.8 Hypothesis test for a single mean (A-level only)

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Question 17

The lifespan of a certain brand of light bulb is normally distributed with a mean of 1200 hours and a standard deviation of 80 hours.

a.

Find the probability that a randomly selected light bulb lasts for less than 1050 hours.

[2]
b.

An engineer claims that the manufacturing process has changed, causing the mean lifespan to decrease.

State the engineer's null and alternative hypotheses.

[1]
c.

A sample of 30 light bulbs is tested and the mean lifespan is found to be 1175 hours.

Carry out a test at the 10% significance level to determine if there is evidence that the mean lifespan is less than 1200 hours.

[3]
Markscheme

2.5.8 Hypothesis test for a single mean (A-level only) Questions

  1. A Level
  2. /Maths
  3. /2.5.8 Hypothesis test for a single mean (A-level only)

132 exam-style questions on OCR (MEI) A Level Maths 2.5.8 Hypothesis test for a single mean (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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