Edexcel S2 2014 June — Question 2

Exam BoardEdexcel
ModuleS2 (Statistics 2)
Year2014
SessionJune
TopicContinuous Probability Distributions and Random Variables
TypeDirect variance calculation from pdf

2. The amount of flour used by a factory in a week is \(Y\) thousand kg where \(Y\) has probability density function $$\mathrm { f } ( y ) = \left\{ \begin{array} { c c } k \left( 4 - y ^ { 2 } \right) & 0 \leqslant y \leqslant 2
0 & \text { otherwise } \end{array} \right.$$
  1. Show that the value of \(k\) is \(\frac { 3 } { 16 }\) Use algebraic integration to find
  2. the mean number of kilograms of flour used by the factory in a week,
  3. the standard deviation of the number of kilograms of flour used by the factory in a week,
  4. the probability that more than 1500 kg of flour will be used by the factory next week.