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NDA 2013
Exam
NDA
Year
2013
Subject
Mathematics
Chapter
Statistics

NDA 2013 · Mathematics · Statistics

The mean of 20 observations is 15. On checking, it was found that...

The mean of 20 observations is 15. On checking, it was found that two observation were wrongly copied as 3 and 6. If wrong observations are replaced by correct values 8 and 4 , then the correct mean is

Options

  1. A15
  2. B15.15
  3. C15.35
  4. D16

Correct answer

B. 15.15

Step-by-step solution

Difference in values =(8+4)−(6+3)=3=(8+4)-(6+3)=3 Mean difference =320=0.15=\frac{3}{20}=0.15 Hence, correct mean =15.15=15.15
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