CAIE Further Paper 4 2021 November — Question 2

Exam BoardCAIE
ModuleFurther Paper 4 (Further Paper 4)
Year2021
SessionNovember
TopicContinuous Probability Distributions and Random Variables
TypePDF from CDF

2 The continuous random variable \(X\) has cumulative distribution function F given by $$F ( x ) = \left\{ \begin{array} { l c } 0 & x < - 1
\frac { 1 } { 2 } ( 1 + x ) ^ { 2 } & - 1 \leqslant x \leqslant 0
1 - \frac { 1 } { 2 } ( 1 - x ) ^ { 2 } & 0 < x \leqslant 1
1 & x > 1 \end{array} \right.$$
  1. Find the probability density function of \(X\).
  2. Find \(\mathrm { P } \left( - \frac { 1 } { 2 } \leqslant X \leqslant \frac { 1 } { 2 } \right)\).
  3. Find \(\mathrm { E } \left( X ^ { 2 } \right)\).
  4. Find \(\operatorname { Var } \left( X ^ { 2 } \right)\).