OCR S4 2010 June — Question 1

Exam BoardOCR
ModuleS4 (Statistics 4)
Year2010
SessionJune
TopicDiscrete Random Variables
TypeCovariance calculation and independence

1 For the variables \(A\) and \(B\), it is given that \(\operatorname { Var } ( A ) = 9 , \operatorname { Var } ( B ) = 6\) and \(\operatorname { Var } ( 2 A - 3 B ) = 18\).
  1. Find \(\operatorname { Cov } ( A , B )\).
  2. State with a reason whether \(A\) and \(B\) are independent.