(i)[4]
Construct the probability distribution table for $X$.
(ii)[2]
It is given that $\text{E}(X) = \frac{6}{7}$. Find the value of $\operatorname{Var}(X)$.
Mathematics 9709 · AS & A Level · Linear combinations of random variables
Linear combinations of random variables — practice question
Mrs Rupal selects $3$ animals at random from $5$ dogs and $2$ cats. Let the random variable $X$ represent the number of cats selected.
Worked solution & mark scheme
This 6-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Probability distribution table accurately set out with $X=0,1,2$ and at least one correct probability” …
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