Edexcel FS1 2021 June — Question 6

Exam BoardEdexcel
ModuleFS1 (Further Statistics 1)
Year2021
SessionJune
TopicProbability Generating Functions
TypeGiven PGF manipulation and properties

  1. The probability generating function of the random variable \(X\) is
$$\mathrm { G } _ { X } ( t ) = k ( 1 + 2 t ) ^ { 5 }$$ where \(k\) is a constant.
  1. Show that \(k = \frac { 1 } { 243 }\)
  2. Find \(\mathrm { P } ( X = 2 )\)
  3. Find the probability generating function of \(W = 2 X + 3\) The probability generating function of the random variable \(Y\) is $$\mathrm { G } _ { Y } ( t ) = \frac { t ( 1 + 2 t ) ^ { 2 } } { 9 }$$ Given that \(X\) and \(Y\) are independent,
  4. find the probability generating function of \(U = X + Y\) in its simplest form.
  5. Use calculus to find the value of \(\operatorname { Var } ( U )\)