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Test of Mathematics for University Admission

TMUA Statistics questions

1 original TMUA statistics questions in the real exam style, each with a step-by-step worked solution and an explanation of why the tempting wrong answers are wrong. Try each one before opening the solution.

Methods on this page: Work with totals, not means

Question 1TMUA Paper 1Warm-up

The mean of 5 numbers is 1212. When one of the numbers is removed, the mean of the remaining 4 numbers is 88. What number was removed?
  1. A44
  2. B2020
  3. C2828
  4. D2929
  5. E3333
Show the answer and worked solution

Answer: C · Method: Work with totals, not means

  1. The original total is 5×12=605 \times 12 = 60.
  2. The new total is 4×8=324 \times 8 = 32.
  3. So the removed number is 60−32=2860 - 32 = 28.

Why the tempting wrong answers are wrong

  • A: That's the change in the mean, not the number removed.
  • B: Work with totals: the removed number is the old total minus the new total.

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