The mass of a high-precision turbine blade, M M\,M grams, is modeled by a normal distribution with a mean of 450.5 g and a standard deviation of 1.8 g. A quality control engineer selects a random sample of 20 blades from a large production batch. Determine the probability that the mean mass of these 20 blades, Mˉ\bar{M}Mˉ, is greater than 451.2 g.
225 exam-style questions on CCEA A Level Maths 4.5.1 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.