(i)[3]
Construct the probability distribution table for $X$.
(ii)[3]
Find $\mathrm{Var}(X)$.
(iii)[3]
Find the probability that $X$ is equal to 1, given that $X$ is non-zero.
Mathematics 9709 · AS & A Level · Linear combinations of random variables
Linear combinations of random variables — practice question
A fair red spinner has 4 sides, labelled $1, 2, 3, 4$. A fair blue spinner has 3 sides, labelled $1, 2, 3$. Each spinner’s score is the number on the side where it comes to rest. Both spinners are spun simultaneously. The random variable $X$ represents the score on the red spinner minus the score on the blue spinner.
Worked solution & mark scheme
This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Completed probability distribution table with entries that total $1$” …
- Full mark scheme, point by point
- Step-by-step worked solution
- Write your answer & get it marked instantly by AI