Edexcel S2 2020 October — Question 6

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2020
SessionOctober
TopicCentral limit theorem
TypeDeriving sampling distribution

6. (a) Explain what you understand by the sampling distribution of a statistic. A factory produces beads in bags for craft shops. A small bag contains 40 beads, a medium bag contains 80 beads and a large bag contains 150 beads. The factory produces small, medium and large bags in the ratio 5:3:2 respectively. A random sample of 3 bags is taken from the factory.
(b) Find the sampling distribution for the range of the number of beads in the 3 bags in the sample. A random sample of \(n\) sets of 3 bags is taken. The random variable \(Y\) represents the number of these \(n\) sets of 3 bags that have a range of 70
(c) Calculate the minimum value of \(n\) such that \(\mathrm { P } ( Y = 0 ) < 0.2\)