Statisticshard · Past Paper
The combined mean of two groups of 40 and 60 observations are 25 and 30 respectively. The combined mean is:
A27.5
B28
C27
D29
✓ Correct Answer: B — 28
Mean = (40*25 + 60*30) / 100 = (1000 + 1800) / 100 = 28.
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