The mass of a bag of flour produced at a factory is normally distributed with a mean of 1500 g and a standard deviation of 20 g.
Find the probability of a bag weighing more than 1545 g.
The quality control manager suspects that the mean mass of the flour bags has changed.
Write down a null and alternative hypothesis for a two-tailed test.
They take a random sample of 25 bags and find a mean mass of 1512 g.
Test at the 5% significance level whether there is evidence that the mean mass has changed.
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.