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NDA 2020
Exam
NDA
Year
2020
Subject
Mathematics
Chapter
Statistics

NDA 2020 · Mathematics · Statistics

The arithmetic mean of 100 observations is 40. Later, it was found...

The arithmetic mean of 100 observations is 40. Later, it was found that an observation '53' was wrongly read as ' 83 '. What is the correct arithmetic mean?

Options

  1. A39.8
  2. B39.7
  3. C39.6
  4. D39.5

Correct answer

B. 39.7

Step-by-step solution

Correct arithmetic mean =40+(−83+53)100=40+(−30)100=39.7.=40+\frac{(-83+53)}{100}=40+\frac{(-30)}{100}=39.7.
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