Question
The standard deviation of 100 observations is 10. If 20 is added to each observation, then what will be the new standard deviation?
NDA
Mathematics
Statistics
2025
NDA 2025 (Phase 2)
NDA Mathematics Question (2025) — Solution
Options
- A. 10
- B. 15
- C. 20
- D. 25
Answer
A. 10
Step-by-step solution
The standard deviation of a set of observations is independent of the change of origin. If a constant is added to or subtracted from each observation, the standard deviation remains unchanged. Given that the original standard deviation is 10. When 20 is added to each observation, the new standard deviation will still be 10. Answer: 10
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