2026 · Q91
If the mean of a set of 7 observations is 10 and the mean of a set of 3 observations is 5, then what is the combined mean?
Elementary MathematicsStatistics
- A9
- B8.5
- C6.5
- D5.5
Explanation
The combined mean is the weighted average of the two group means. That is (7·10 + 3·5)/(7 + 3) = 85/10 = 8.5. Hence the answer is 8.5, option B.