The length of the bus journey from Leeds to London is normally distributed with a mean of 200 minutes and a standard deviation of 10 minutes.
Find the probability of a bus taking longer than 220 minutes.
The bus company suspects that the mean bus time has changed.
Write down a null and alternative hypothesis for a two-tailed test.
They take a sample of 4 bus journeys and find a mean time of 210 minutes.
Test at the 1% significance level whether there is evidence that the mean time has changed.
591 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.