Edexcel FS2 2023 June — Question 6

Exam BoardEdexcel
ModuleFS2 (Further Statistics 2)
Year2023
SessionJune
TopicCumulative distribution functions
TypeCDF with additional constraints

  1. The continuous random variable \(X\) has cumulative distribution function given by
$$F ( x ) = \left\{ \begin{array} { c r } 0 & x < 0
k \left( x - a x ^ { 2 } \right) & 0 \leqslant x \leqslant 4
1 & x > 4 \end{array} \right.$$ The values of \(a\) and \(k\) are positive constants such that \(\mathrm { P } ( X < 2 ) = \frac { 2 } { 3 }\)
  1. Find the exact value of the median of \(X\)
  2. Find the probability density function of \(X\)
  3. Hence, deduce the value of the mode of \(X\), giving a reason for your answer.