The mass of beans in a tin filled by a machine, in grams, is Normally distributed with mean 415 g and standard deviation 3.4 g.
Find the probability that a randomly chosen tin contains less than 409 g of beans. Give your answer to 3 significant figures.
The company suspects that the machine is now filling tins to a mean mass of less than 415 g. A random sample of 20 tins is taken, and the mean mass of beans in the sample is 413 g.
Stating your hypotheses clearly, carry out a test at the 1% significance level to investigate the company's suspicion. You may assume that the standard deviation is still 3.4 g.
284 exam-style questions on CCEA A Level Maths 4.5 Statistical distributions (A-level only), covering 4.5.1 Statistical distributions (A-level only) and 4.5.2 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.