AQA Further AS Paper 2 Statistics 2020 June — Question 5

Exam BoardAQA
ModuleFurther AS Paper 2 Statistics (Further AS Paper 2 Statistics)
Year2020
SessionJune
TopicDiscrete Probability Distributions
TypeCalculate Var(aX+b) transformations

5 The discrete random variable \(X\) has the following probability distribution.
\(\boldsymbol { x }\)\(\mathbf { 2 }\)\(\mathbf { 4 }\)\(\mathbf { 6 }\)\(\mathbf { 9 }\)
\(\mathbf { P } ( \boldsymbol { X } = \boldsymbol { x } )\)0.20.60.10.1
5
  1. Find \(\mathrm { P } ( X \leq 6 )\) 5
  2. Let \(Y = 3 X + 2\)
    Show that \(\operatorname { Var } ( Y ) = 32.49\)
    5
  3. The continuous random variable \(T\) is independent of \(Y\). Given that \(\operatorname { Var } ( T ) = 5\), find \(\operatorname { Var } ( T + Y )\)