Mathematics 9709 · AS & A Level · Sampling and estimation
Sampling and estimation — practice question
In Quarendon, $66\%$ of households report being satisfied with the speed of their wifi connection.
(i)[3]
Find the probability that, from 10 households selected at random in Quarendon, at least 8 are satisfied with the speed of their wifi connection.
(ii)[5]
A random sample of 150 households in Quarendon is chosen. Use an appropriate approximation to determine the probability that more than 84 are satisfied with the speed of their wifi connection.
Worked solution & mark scheme
This 8-mark question has a full step-by-step worked solution and mark scheme. One marking point: “Valid binomial expression, for example ${}^{10}C_8(0.66)^8(0.34)^2+{}^{10}C_9(0.66)^9(0.34)+0.66^{10}$” …