Mathematics 9709 · AS & A Level · Discrete random variables
Discrete random variables — practice question
There are three fair 4-sided spinners, each labelled $1, 2, 3, 4$ on its sides. They are spun together, and the number showing on each spinner is noted. The random variable $X$ is the largest number recorded.
(a)[3]
Show that the result is $P(X = 2) = \frac{7}{64}$.
(b)[2]
Complete the probability distribution table for $X$.
(c)[1]
On a different occasion, one of the fair 4-sided spinners is spun again and again until a $3$ appears. The random variable $Y$ is the number of spins needed to get a $3$. Find the value of $P(Y = 6)$.
(d)[2]
Find the value of $P(Y > 4)$.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Seven valid outcomes that give score 2” …