The mass of flour in bags packed by a factory is normally distributed with a mean of 1500 g and a standard deviation of 25 g.
Find the probability that a randomly selected bag of flour has a mass of less than 1450 g.
A quality inspector believes the bagging machine is under-filling and the mean mass is less than 1500 g.
State the null and alternative hypotheses for this test.
A random sample of 16 bags is weighed and the mean mass is found to be 1485 g.
Test the inspector's belief at the 1% significance level.
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.