Variation 2 · answer guide
Binomial distribution — Small p, still larger than p
Question
If and , which is true?
This practice question was inspired by Question 6 in the 2021 NSW HSC Mathematics Extension 1 examination, © NESA. It is an original TestMum variation that practises the same mathematical idea, not an official NESA question.
Step by step
- Set up the solution: identify the random variable and its parameters before using the matching probability formula..
- Match the result to the choices and state the correct option.Therefore option A is correct.
Common mistake: changing so many features that the new example no longer tests the same mathematical idea.
Verification: Complement of all failures always exceeds a single-trial success probability when and .
Any mark labels are a TestMum study aid, not an official NESA marking allocation.
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