OCR MEI Paper 2 2018 June — Question 10

Exam BoardOCR MEI
ModulePaper 2 (Paper 2)
Year2018
SessionJune
TopicNormal Distribution
TypeFind percentile from probability

10 The screenshot in Fig. 10 shows the probability distribution for the continuous random variable \(X\), where \(X \sim \mathrm {~N} \left( \mu , \sigma ^ { 2 } \right)\). \begin{figure}[h]
\includegraphics[alt={},max width=\textwidth]{d8ff9511-aff7-45ea-ba55-e6667e8ba760-06_515_1009_338_529} \captionsetup{labelformat=empty} \caption{Fig. 10}
\end{figure} The area of each of the unshaded regions under the curve is 0.025 . The lower boundary of the shaded region is at 16.452 and the upper boundary of the shaded region is at 21.548 .
  1. Calculate the value of \(\mu\).
  2. Calculate the value of \(\sigma ^ { 2 }\).
  3. \(Y\) is the random variable given by \(Y = 4 X + 5\).
    (A) Write down the distribution of \(Y\).
    (B) Find \(\mathrm { P } ( \mathrm { Y } > 90 )\).