Edexcel S2 — Question 6

Exam BoardEdexcel
ModuleS2 (Statistics 2)
TopicContinuous Probability Distributions and Random Variables
TypeFind mode of distribution

6. A random variable \(X\) has a probability density function given by $$\begin{array} { l l } \mathrm { f } ( x ) = \frac { 4 x ^ { 2 } ( 3 - x ) } { 27 } & 0 \leq x \leq 3
\mathrm { f } ( x ) = 0 & \text { otherwise. } \end{array}$$
  1. Find the mode of \(X\).
  2. Find the mean of \(X\).
  3. Specify completely the cumulative distribution function of \(X\).
  4. Deduce that the median, \(m\), of \(X\) satisfies the equation \(m ^ { 4 } - 4 m ^ { 3 } + 13 \cdot 5 = 0\), and hence show that \(1.84 < m < 1.85\).
  5. What do these results suggest about the skewness of the distribution?