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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 35

The operational endurance of a random sample of 15 'Volt-X' industrial sensors is measured under standard load. The mean endurance of the sample is recorded as 118.4 hours118.4\text{ hours}118.4 hours. The endurance times of these sensors are known to follow a normal distribution.

Given that the population standard deviation for these sensors is 4.2 hours4.2\text{ hours}4.2 hours,

a.

estimate the limits between which 95%95\%95% of the endurance times of individual sensors lie.

[2]
b.

find a 98%98\%98% confidence interval for the mean endurance time of the 'Volt-X' sensors.

[3]
c.

A quality control engineer claims that the true mean endurance time of these sensors is 121.5 hours121.5\text{ hours}121.5 hours.

Comment on the engineer's claim. Give a reason for your answer.

[2]
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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