The weights of a random sample of 12 luxury chocolates are measured. The mean weight of the sample is recorded as 42.5 g42.5\text{ g}42.5 g. The weights of the chocolates are known to be normally distributed.
Given that the population standard deviation is 0.8 g0.8\text{ g}0.8 g,
estimate the limits between which 95%95\%95% of the weights of individual chocolates lie.
find a 99%99\%99% confidence interval for the mean weight of the chocolates.
A quality control manager claims that the mean weight of these chocolates is 41.8 g41.8\text{ g}41.8 g.
Comment on the manager's claim. Give a reason for your answer.
162 exam-style questions on AQA A Level Maths 2.5 O: Statistical hypothesis testing, covering 2.5.1 Language of hypothesis testing, 2.5.2 Hypothesis test for a binomial proportion, and 2.5.3 Hypothesis test for a Normal mean (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.