Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
In country X, $25\%$ of people have fair hair, whereas in country Y the proportion is $60\%$. Country X has 20 million people and country Y has 8 million people. One person is selected at random from this total of 28 million people.
(i)[1]
Find the probability that the selected person comes from country X.
(ii)[2]
Find the probability that the selected person has fair hair.
(iii)[2]
Find the probability that the selected person is from country X, given that the person has fair hair.
Worked solution & mark scheme
This 5-mark question has a full step-by-step worked solution and mark scheme. One marking point: “A correct expression for $P(X)$, for example $\frac{20}{28}\times \frac{5}{7}$” …