Edexcel S2 2014 June — Question 6

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2014
SessionJune
TopicCumulative distribution functions
TypeCDF to PDF derivation

6. A continuous random variable \(X\) has cumulative distribution function \(\mathrm { F } ( x )\) given by $$F ( x ) = \left\{ \begin{array} { l c } 0 & x < 0
\frac { x ^ { 2 } } { 20 } ( 9 - 2 x ) & 0 \leqslant x \leqslant 2
1 & x > 2 \end{array} \right.$$
  1. Verify that the median of \(X\) lies between 1.23 and 1.24
  2. Specify fully the probability density function \(\mathrm { f } ( x )\).
  3. Find the mode of \(X\).
  4. Describe the skewness of this distribution. Justify your answer.