Edexcel S2 2019 January — Question 5

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2019
SessionJanuary
TopicContinuous Uniform Random Variables
TypeFind parameters from given statistics

  1. The continuous random variable \(X\) is uniformly distributed over the interval \([ a , b ]\) where \(0 < a < b\)
Given that \(\mathrm { P } ( X < b - 2 a ) = \frac { 1 } { 3 }\)
    1. show that \(\mathrm { E } ( X ) = \frac { 5 a } { 2 }\)
    2. find \(\mathrm { P } ( X > b - 4 a )\) The continuous random variable \(Y\) is uniformly distributed over the interval [3, c] where \(c > 3\) Given that \(\operatorname { Var } ( Y ) = 3 c - 9\), find
    1. the value of \(c\)
    2. \(\mathrm { P } ( 2 Y - 7 < 20 - Y )\)
    3. \(\mathrm { E } \left( Y ^ { 2 } \right)\)