Q75.If ∑9i=1(xi −5) = 9 and ∑9i=1 (xi −5)2 = 45, then the standard deviation of the 9 items x1, x2, … . , x9 is (1) 3 (2) 9 (3) 4 (4) 2
What This Question Tests
This question directly tests the definition and calculation of standard deviation from given sums involving deviations from a fixed value, using the property that standard deviation is invariant to a change of origin.
Concepts Tested
Formulas Used
Mean x̄ = Σx / n
Variance σ^2 = (Σ(x_i - x̄)^2) / n
Standard Deviation σ = √Variance
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📋 Question Details
- Chapter
- Statistics
- Topic
- Standard deviation
- Year
- 2018
- Shift
- 08 Apr
- Q Number
- Q75
- Type
- MCQ
- NCERT Ref
- Class 11 Mathematics Ch 15: Statistics
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