Practice variation 3 of 3
Binomial distribution — Smaller $n$, different $p$
Your question
A manager claims only of calls go unanswered. In a sample of calls, are unanswered.
(i) Using the normal approximation to the binomial (without continuity correction), calculate for . Hence,
(ii) Explain why the normal-approximation method might not be valid.
This practice question was inspired by Question 13(e) in the 2022 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
- Have you stated every choice or assumption?
- Can another student follow each line?
- Did you verify the final result independently?