The scores on a standardised aptitude test are modelled by a Normal distribution with mean 50 and standard deviation 8.
Using this model, find the probability that a randomly chosen candidate scores more than 65. Give your answer to 3 significant figures.
A researcher claims that the mean score of candidates from a particular region is higher than 50. A random sample of 64 candidates from this region has a mean score of 52.
Stating your hypotheses clearly, test the researcher's claim at the 5% significance level. You may assume that the standard deviation is 8 for this region.
351 exam-style questions on AQA A Level Maths 2.4.2 The Normal distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.