Edexcel S2 — Question 6

Exam BoardEdexcel
ModuleS2 (Statistics 2)
TopicApproximating Binomial to Normal Distribution
TypeCombined binomial and normal events

6. In a particular parliamentary constituency, the percentage of Conservative voters at the last election was \(35 \%\), and the percentage who voted for the Monster Raving Loony party was \(2 \%\).
  1. Find the probability that a random sample of 10 electors includes at least two Conservative voters. Use suitable approximations to find
  2. the probability that a random sample of 500 electors will include at least 200 who voted either Conservative or Monster Raving Loony,
  3. the probability that a random sample of 200 electors will have at least 5 Monster Raving Loony voters in it.
  4. One of (b) or (c) requires an adjustment to be made before a calculation is done. Explain what this adjustment is, and why it is necessary.