A sample of size 12 is to be taken from a population that is normally distributed with mean 82 and standard deviation 5. Find the probability that the sample mean will be less than 80.
390 exam-style questions on AQA A Level Maths 2.4 N: Statistical distributions, covering 2.4.1 Discrete distributions and the binomial, 2.4.2 The Normal distribution (A-level only), and 2.4.3 Selecting an appropriate distribution (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.