Edexcel S2 2015 June — Question 3

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2015
SessionJune
TopicContinuous Uniform Random Variables
TypeBreaking/cutting problems

  1. A piece of spaghetti has length \(2 c\), where \(c\) is a positive constant. It is cut into two pieces at a random point. The continuous random variable \(X\) represents the length of the longer piece and is uniformly distributed over the interval \([ c , 2 c ]\).
    1. Sketch the graph of the probability density function of \(X\)
    2. Use integration to prove that \(\operatorname { Var } ( X ) = \frac { c ^ { 2 } } { 12 }\)
    3. Find the probability that the longer piece is more than twice the length of the shorter piece.