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NTA Abhyas 2020
Exam
NTA Abhyas
Year
2020
Subject
Mathematics
Chapter
Statistics

NTA Abhyas 2020 · Mathematics · Statistics

Coefficient of variation of two distributions are 60% and 75%, and...

Coefficient of variation of two distributions are 6060% and 7575%, and their standard deviation are 1818 and 1515 respectively, then their arithmetic means respectively are

Options

  1. A30,3030, 30
  2. B30,2030, 20
  3. C20,3020, 30
  4. D20,2020, 20

Correct answer

B. 30,2030, 20

Step-by-step solution

Given, CV1=60,CV2=75,σ1=18C{V}_{1} = 60, {CV}_{2} = 75, {\sigma}_{1} = 18 and σ2=15{\sigma}_{2} = 15
Let x−1{\overset{-}{x}}_{1} and x−2{\overset{-}{x}}_{2} be the means of 1st{1}^{st} and 2nd{2}^{nd} distribution respectively.
Then, CV1=σ1x−1×100⇒x−1=18×10060=30C{V}_{1} = \dfrac{{\sigma}_{1}}{{\overset{-}{x}}_{1}} \times 100 ⇒ {\overset{-}{x}}_{1} = \dfrac{18 \times 100}{60} = 30
CV2=σ2x−2×100⇒x−2=15×10075=20C{V}_{2} = \dfrac{{\sigma}_{2}}{{\overset{-}{x}}_{2}} \times 100 ⇒ {\overset{-}{x}}_{2} = \dfrac{15 \times 100}{75} = 20
Hence, x−1=30{\overset{-}{x}}_{1} = 30 and x−2=20{\overset{-}{x}}_{2} = 20
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