Edexcel S1 2013 June — Question 3

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2013
SessionJune
TopicConditional Probability
TypeBasic two-way table probability

3. In a company the 200 employees are classified as full-time workers, part-time workers or contractors.
The table below shows the number of employees in each category and whether they walk to work or use some form of transport.
\cline { 2 - 3 } \multicolumn{1}{c|}{}WalkTransport
Full-time worker28
Part-time worker3575
Contractor3050
The events \(F , H\) and \(C\) are that an employee is a full-time worker, part-time worker or contractor respectively. Let \(W\) be the event that an employee walks to work. An employee is selected at random.
Find
  1. \(\mathrm { P } ( H )\)
  2. \(\mathrm { P } \left( [ F \cap W ] ^ { \prime } \right)\)
  3. \(\mathrm { P } ( W \mid C )\) Let \(B\) be the event that an employee uses the bus.
    Given that \(10 \%\) of full-time workers use the bus, \(30 \%\) of part-time workers use the bus and \(20 \%\) of contractors use the bus,
  4. draw a Venn diagram to represent the events \(F , H , C\) and \(B\),
  5. find the probability that a randomly selected employee uses the bus to travel to work.