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.
Find the probability that XXX is within 1.01.01.0 ohm of rrr.
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.
Given that the mean of these 25 measurements is 120.4120.4120.4 ohms, find a 95%95\%95% confidence interval for rrr.
Practise Edexcel A Level Maths The Normal Distribution with exam-style questions for A Level Maths. 100 questions covering The Normal Distribution, Finding Probabilities for Normal Distributions, The Inverse Normal Distribution Function, The Standard Normal Distribution, Finding the mean and standard deviation, Approximating a Binomial Distribution, and Hypothesis Testing with the Normal Distribution, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.