(a)[3]
Complete the probability distribution table for $X$, with the probabilities expressed as numerical fractions.
(b)[1]
Find the value of $\text{E}(X)$.
(c)[2]
Find $P(X \ne 2 \mid X > 0)$.
Mathematics 9709 · AS & A Level · Discrete random variables
Discrete random variables — practice question
The random variable $X$ can take the value $x$ with probability $kx^2$, where $k$ is a constant, and the only possible values of $x$ are $-2$, $1$, $2$ and $3$.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Apply sum of probabilities = 1: $4k+k+4k+9k=1$, which gives $18k=1$” …
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