Q69.The mean and variance of 7 observations are 8 and 16 respetively. If two observations are 6 and 8, then the variance of the remaining 5 observations is : (1) 92 (2) 134 5 5 112 536 (3) (4) 5 25
What This Question Tests
This question involves using the definitions of mean and variance for a complete set of observations to find the sum of observations and sum of squares, and then using these to calculate the variance of the remaining subset.
Concepts Tested
Formulas Used
Mean (X̄) = Σxᵢ / n
Variance (σ²) = (Σxᵢ² / n) - (X̄)²
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📋 Question Details
- Chapter
- Statistics
- Topic
- Mean and variance of ungrouped data
- Year
- 2021
- Shift
- 31 Aug Shift 2
- Q Number
- Q69
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 15: Statistics
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