Solved UPSC CDS/OTA Question
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Q · Statistics Moderate · 45s
Group A has 4 observations (18, 20, 22, 24) and Group B has 3 observations (30, 32, 34). Find the combined mean.
TopicStatistics
Question Typemultiple choice
DifficultyModerate
Marking+1 / −0.33
Test Duration30 min
Step-by-Step Solution
The complete worked solution.
Every step explained - no skipped algebra.
Combined mean = (n₁x̄₁ + n₂x̄₂)/(n₁+n₂) = (4×21.00 + 3×32.00)/7 = 25.71.
Final Answer: Option D - 25.71