2. A spinner can land on the numbers \(2,4,5,7\) or 8 only.
The random variable \(X\) represents the number that this spinner lands on when it is spun once. The probability distribution of \(X\) is given in the table below.
| \(\boldsymbol { x }\) | 2 | 4 | 5 | 7 | 8 |
| \(\mathbf { P } ( \boldsymbol { X } = \boldsymbol { x } )\) | 0.25 | 0.3 | 0.2 | 0.1 | 0.15 |
- Find \(\mathrm { P } ( 2 X - 3 > 5 )\)
Given that \(\mathrm { E } ( X ) = 4.6\)
- show that \(\operatorname { Var } ( X ) = 4.14\)
The random variable \(Y = a X - b\) where \(a\) and \(b\) are positive constants.
Given that
$$\mathrm { E } ( Y ) = 13.4 \quad \text { and } \quad \operatorname { Var } ( Y ) = 66.24$$ - find the value of \(a\) and the value of \(b\)
In a game Sam and Alex each spin the spinner once, landing on \(X _ { 1 }\) and \(X _ { 2 }\) respectively.
Sam's score is given by the random variable \(S = X _ { 1 }\)
Alex's score is given by the random variable \(R = 2 X _ { 2 } - 3\)
The person with the higher score wins the game. If the scores are the same it is a draw. - Find the probability that Sam wins the game.