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

  1. A. 10
  2. B. 15
  3. C. 20
  4. D. 25

Correct Answer: A. 10

Explanation

Adding or subtracting a constant to each observation in a dataset shifts the mean by that constant but does not change the spread or variance of the data. Thus, the standard deviation remains unchanged at 10.

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