← Start with the original worked guide: Question 12(b)

Practice variation 1 of 3

Binomial distribution — New n and p

Your question

Let .

(i) Find .

(ii) Show . Hence,

(iii) Using a normal approximation and , estimate as a one-standard-deviation style statement (nearest empirical-rule percentage).

This practice question was inspired by Question 12(b) in the 2020 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.

Before you check

Open the step-by-step answer guide →