SPS SPS FM Statistics 2024 September — Question 7

Exam BoardSPS
ModuleSPS FM Statistics (SPS FM Statistics)
Year2024
SessionSeptember
TopicContinuous Probability Distributions and Random Variables
TypeCalculate and compare mean, median, mode

7. The continuous random variable \(X\) has the following probability density function: $$f ( x ) = \begin{cases} a + b x & 0 \leqslant x \leqslant 2
0 & \text { otherwise } \end{cases}$$ where \(a\) and \(b\) are constants.
  1. Show that \(2 a + 2 b = 1\).
  2. It is given that \(\mathrm { E } ( X ) = \frac { 11 } { 9 }\). Use this information to find a second equation connecting \(a\) and \(b\), and hence find the values of \(a\) and \(b\).
  3. Determine whether the median of \(X\) is greater than, less than, or equal to \(\mathrm { E } ( X )\).
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