The length of the bus journey from Leeds to London is normally distributed with a mean of 220 minutes and a standard deviation of 8 minutes.
Find the probability of a bus taking longer than 235 minutes.
The bus company suspect that the mean bus time has changed.
They take a sample of 10 bus journeys and find a mean time of 230 minutes.
Write down a null and alternative hypothesis for a two-tailed test and test at the 1% significance level whether there is evidence that the mean time has changed.
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.