OCR S3 2014 June — Question 6

Exam BoardOCR
ModuleS3 (Statistics 3)
Year2014
SessionJune
TopicContinuous Probability Distributions and Random Variables
TypePiecewise PDF with k

6 The continuous random variable \(X\) has probability density function given by $$\mathrm { f } ( x ) = \left\{ \begin{array} { c l } k \sin x & 0 \leqslant x \leqslant \frac { 1 } { 2 } \pi ,
k \left( 2 - \frac { 2 x } { \pi } \right) & \frac { 1 } { 2 } \pi \leqslant x \leqslant \pi ,
0 & \text { otherwise, } \end{array} \right.$$ where \(k\) is a constant.
  1. Show that \(k = \frac { 4 } { 4 + \pi }\).
  2. Find \(\mathrm { E } ( X )\), correct to 3 significant figures, showing all necessary working.