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.
616 exam-style questions on Edexcel A Level Maths The Normal Distribution, covering 3.1 The Normal Distribution, 3.2 Finding Probabilities for Normal Distributions, 3.3 The Inverse Normal Distribution Function, 3.4 The Standard Normal Distribution, 3.5 Finding the mean and standard deviation, 3.6 Approximating a Binomial Distribution, and 3.7 Hypothesis Testing with the Normal Distribution. Each one has a worked solution and a mark scheme showing where the marks go.