WAEC 2025 · Paper 1 · Q47✱✱

Statistics: data & averages

The mean of 20 observations is 4. If the largest observation, 23, is removed, find the mean of the remaining observations.

Worked solution (try it first)

Total of the 20 observations: $20 \times 4 = 80$ .
Remove 23: the total is $80 - 23 = 57$ for 19 observations.
The new mean is $\frac{57}{19} = 3$ , option D.

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