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NDA 2020
Exam
NDA
Year
2020
Subject
Mathematics
Chapter
Statistics

NDA 2020 · Mathematics · Statistics

The sum of deviations of n number of observations measured from 2.5...

The sum of deviations of nn number of observations measured from 2.5 is 50. The sum of deviations of the same set of observations measured from 3.5 is -50. What is the value of nn ?

Options

  1. A50
  2. B60
  3. C80
  4. D100

Correct answer

D. 100

Step-by-step solution

Number of data set =n=n. Mean =2.5=2.5 Sum of deviations =50=50 Again, sum of deviations, when mean =3.5=3.5 is -50. So, (3.5−2.5)×n=50−(−50)∴n=100(3.5-2.5) \times n=50-(-50)\therefore n=100
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