The mass of an item has mean 500 g and standard deviation 12 g. Independent items are selected in samples of 25, and the population is Normal.
State the distribution of the sample mean X‾\overline XX.
Find P(X‾>504)P(\overline X>504)P(X>504).
328 exam-style questions on WJEC A Level Maths 4.2 Statistical distributions (A-level only), covering 4.2.1 Statistical distributions (A-level only), 4.2.2 Statistical distributions (A-level only), and 4.2.3 Statistical distributions (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.