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2.4.2 The Normal distribution (A-level only)

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Question 51

An electronics engineer measures the resistance, rrr ohms, of a specific component. The measured resistance, XXX ohms, is normally distributed with mean rrr ohms and standard deviation 0.80.80.8 ohms.

a.

Find the probability that XXX is within 1.01.01.0 ohm of rrr.

[2]
b.

The same component is measured 25 times and the results are recorded.

Find the probability that the sample mean of these 25 results, Xˉ\bar{X}Xˉ, is within 0.40.40.4 ohms of rrr.

[3]
c.

Given that the mean of these 25 measurements is 120.4120.4120.4 ohms, find a 95%95\%95% confidence interval for rrr.

[3]
Markscheme

2.4.2 The Normal distribution (A-level only) Questions

  1. A Level
  2. /Maths
  3. /2.4.2 The Normal distribution (A-level only)

351 exam-style questions on AQA A Level Maths 2.4.2 The Normal distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.

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