Q85.The mean and variance of 10 observations were calculated as 15 and 15 respectively by a student who took by mistake 25 instead of 15 for one observation. Then, the correct standard deviation is _______.
What This Question Tests
This question requires recalculating the mean and variance when an observation is incorrectly recorded, and then finding the correct standard deviation.
Concepts Tested
Formulas Used
Mean = Σx_i / n
Variance = (Σx_i² / n) - (Mean)²
Corrected Σx = Original Σx - Wrong value + Correct value
Corrected Σx² = Original Σx² - (Wrong value)² + (Correct value)²
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📋 Question Details
- Chapter
- Statistics
- Topic
- Mean and Variance of ungrouped data
- Year
- 2022
- Shift
- 27 Jul Shift 1
- Q Number
- Q85
- Type
- Numerical
- NCERT Ref
- Class 11 Mathematics Ch 15: Statistics
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