OCR MEI Further Statistics Major 2019 June — Question 10

Exam BoardOCR MEI
ModuleFurther Statistics Major (Further Statistics Major)
Year2019
SessionJune
TopicContinuous Probability Distributions and Random Variables
TypeFind parameter from median

10 The probability density function of the continuous random variable \(X\) is given by
\(f ( x ) = \begin{cases} k x ^ { m } & 0 \leqslant x \leqslant a ,
0 & \text { otherwise, } \end{cases}\)
where \(a , k\) and \(m\) are positive constants.
  1. Show that \(k = \frac { m + 1 } { a ^ { m + 1 } }\).
  2. Find the cumulative distribution function of \(X\) in terms of \(x , a\) and \(m\).
  3. Given that \(\mathrm { P } \left( \frac { 1 } { 4 } a < X < \frac { 1 } { 2 } a \right) = \frac { 1 } { 10 }\),
    1. show that \(2 p ^ { 2 } - 10 p + 5 = 0\), where \(p = 2 ^ { m }\),
    2. find the value of \(m\). \section*{END OF QUESTION PAPER}