OCR PURE — Question 11

Exam BoardOCR
ModulePURE
TopicDiscrete Probability Distributions
TypeProbability distribution from formula

11 In this question you must show detailed reasoning. A biased four-sided spinner has edges numbered \(1,2,3,4\). When the spinner is spun, the probability that it will land on the edge numbered \(X\) is given by
\(P ( X = x ) = \begin{cases} \frac { 1 } { 2 } - \frac { 1 } { 10 } x & x = 1,2,3,4 ,
0 & \text { otherwise } . \end{cases}\)
  1. Draw a table showing the probability distribution of \(X\). The spinner is spun three times and the value of \(X\) is noted each time.
  2. Find the probability that the third value of \(X\) is greater than the sum of the first two values of \(X\).