Edexcel S1 2014 June — Question 6

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2014
SessionJune
TopicPrinciple of Inclusion/Exclusion
TypeIndependence Testing with Two Events

6. The Venn diagram below shows the probabilities of customers having various combinations of a starter, main course or dessert at Polly’s restaurant.
\(S =\) the event a customer has a starter.
\(M =\) the event a customer has a main course.
\(D =\) the event a customer has a dessert.
\includegraphics[max width=\textwidth, alt={}, center]{fa0dbe16-ace8-4c44-8404-2bc4e1879d57-10_602_1125_607_413} Given that the events \(S\) and \(D\) are statistically independent
  1. find the value of \(p\).
  2. Hence find the value of \(q\).
  3. Find
    1. \(\quad\) P( \(D \mid M \cap S\) )
    2. \(\operatorname { P } \left( D \mid M \cap S ^ { \prime } \right)\) One evening 63 customers are booked into Polly's restaurant for an office party. Polly has asked for their starter and main course orders before they arrive. Of these 63 customers 27 ordered a main course and a starter, 36 ordered a main course without a starter.
  4. Estimate the number of desserts that these 63 customers will have.