Independence Testing with Two Events

A question is this type if and only if it asks you to determine whether two events are independent by checking if P(A ∩ B) = P(A) × P(B) or equivalent conditions.

2 questions · Moderate -0.6

2.03a Mutually exclusive and independent events
Sort by: Default | Easiest first | Hardest first
Edexcel S1 2014 June Q6
12 marks Moderate -0.3
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.
OCR S4 2015 June Q1
5 marks Moderate -0.8
1 For the events \(A\) and \(B\) it is given that $$\mathrm { P } ( A ) = 0.6 , \mathrm { P } ( B ) = 0.3 \text { and } \mathrm { P } ( A \text { or } B \text { but not both } ) = 0.4 \text {. }$$
  1. Find \(\mathrm { P } ( A \cap B )\).
  2. Find \(\mathrm { P } \left( A ^ { \prime } \cap B \right)\).
  3. State, giving a reason, whether \(A\) and \(B\) are independent.