Statisticshard · Past Paper
Find the missing frequency 'p' if the mean of the data (x: 5, 10, 15; f: 2, p, 3) is 10.5.
A4
B5
C6
D3
✓ Correct Answer: B — 5
Mean = [5(2) + 10(p) + 15(3)] / (2 + p + 3) = 10.5. (55 + 10p) / (5 + p) = 10.5 => 55 + 10p = 52.5 + 10.5p => 2.5 = 0.5p => p = 5.
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