Edexcel S2 2012 January — Question 3

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2012
SessionJanuary
TopicBinomial Distribution
TypeAt least one success

3. The probability of a telesales representative making a sale on a customer call is 0.15 Find the probability that
  1. no sales are made in 10 calls,
  2. more than 3 sales are made in 20 calls. Representatives are required to achieve a mean of at least 5 sales each day.
  3. Find the least number of calls each day a representative should make to achieve this requirement.
  4. Calculate the least number of calls that need to be made by a representative for the probability of at least 1 sale to exceed 0.95