Edexcel S2 2018 June — Question 6

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2018
SessionJune
TopicContinuous Probability Distributions and Random Variables
TypeFind median or percentiles

6. A random variable \(X\) has probability density function given by $$f ( x ) = \left\{ \begin{array} { c c } \frac { 1 } { 4 } & 0 \leqslant x < 1
\frac { x ^ { 3 } } { 5 } & 1 \leqslant x \leqslant 2
0 & \text { otherwise } \end{array} \right.$$
  1. Use algebraic integration to find \(\mathrm { E } ( X )\)
  2. Use algebraic integration to find \(\operatorname { Var } ( X )\)
  3. Define the cumulative distribution function \(\mathrm { F } ( x )\) for all values of \(x\).
  4. Find the median of \(X\), giving your answer to 3 significant figures.
  5. Comment on the skewness of the distribution, justifying your answer.