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NDA 2025 · PYQ · Statistics / Standard deviation transformation · easy

The standard deviation of 100 observations is 10. If 5 is added to each observation and then divided by 20, then what will be the new standard deviation?

  1. A.0.25
  2. B.0.5✓ Correct
  3. C.0.75
  4. D.1.00

Explanation

Adding a constant does not change the standard deviation. Dividing each observation by 20 divides the standard deviation by 20. Therefore the new standard deviation = 10/20 = 0.5.
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