Edexcel S1 2015 January — Question 6

Exam BoardEdexcel
ModuleS1 (Statistics 1)
Year2015
SessionJanuary
TopicDiscrete Probability Distributions
TypeSimple algebraic expression for P(X=x)

  1. The random variable \(X\) has probability function
$$\mathrm { P } ( X = x ) = \frac { x ^ { 2 } } { k } \quad x = 1,2,3,4$$
  1. Show that \(k = 30\)
  2. Find \(\mathrm { P } ( X \neq 4 )\)
  3. Find the exact value of \(\mathrm { E } ( X )\)
  4. Find the exact value of \(\operatorname { Var } ( X )\) Given that \(Y = 3 X - 1\)
  5. find \(\mathrm { E } \left( Y ^ { 2 } \right)\)