OCR MEI Further Statistics Major Specimen — Question 2

Exam BoardOCR MEI
ModuleFurther Statistics Major (Further Statistics Major)
SessionSpecimen
TopicContinuous Probability Distributions and Random Variables
TypePiecewise PDF with k

2 The continuous random variable \(X\) takes values in the interval \(- 1 \leq x \leq 1\) and has probability density function $$f ( x ) = \left\{ \begin{array} { l r } a & - 1 \leq x < 0
a + x ^ { 2 } & 0 \leq x \leq 1 \end{array} \right.$$ where \(a\) is a constant.
  1. (A) Sketch the probability density function.
    (B) Show that \(a = \frac { 1 } { 3 }\).
  2. Find
    (A) \(\mathrm { P } \left( X < \frac { 1 } { 2 } \right)\),
    (B) the mean of \(X\).
  3. Show that the median of \(X\) satisfies the equation \(2 m ^ { 3 } + 2 m - 1 = 0\).