Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
Dayo takes two digits at random, without replacement, from the $9$-digit number $113\,333\,555$.
(i)[3]
Find the probability that the two digits chosen are equal.
(ii)[3]
Find the probability that one digit is a $5$ and the other digit is not a $5$.
(iii)[4]
Find the probability that the first digit Dayo chose was a $5$, given that the second digit he chose is not a $5$.
(iv)[3]
The random variable $X$ gives the number of $5$s that Dayo chooses. Draw up a table to show the probability distribution of $X$.
Worked solution & mark scheme
This 13-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Accurate addition of probabilities $P(1,1)+P(3,3)+P(5,5)$” …