TestMum
← 2022 HSC Extension 1 paper Question 14(d)

Variation 2 · answer guide

Binomial distribution — Mean–seat gap

Question

If and , find and the number of standard deviations from 350.

This practice question was inspired by Question 14(d) 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.

Step by step

  1. Set up the solution: identify the random variable and its parameters before using the matching probability formula..
  2. State the final answer clearly in the form the question requested.; .

Common mistake: changing so many features that the new example no longer tests the same mathematical idea.

Verification: Sanity check that 350 is about 2.3–2.4 sd above the mean.

Any mark labels are a TestMum study aid, not an official NESA marking allocation.

← Back to 2022 HSC Extension 1 paper Question 14(d)