Mathematics 9709 · AS & A Level · Sampling and estimation

Sampling and estimation — practice question

At Nonland Business College, every student takes an accountancy examination at the close of the first year of study. On average, $80\%$ of students succeed in this examination.
(i)[3]

A random sample of 9 students who are due to take this examination is selected. Find the probability that no more than 6 of them will pass the examination.

(ii)[5]

A random sample of 200 students who are due to take this examination is selected. Use an appropriate approximate distribution to find the probability that more than 166 of them will pass the examination.

(iii)[1]

Justify the choice of your approximate distribution in part (ii).

Worked solution & mark scheme

This 9-mark question has a full step-by-step worked solution and mark scheme. One marking point: Use binomial terms to write $1-(P(7)+P(8)+P(9))$

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