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NDA 2012
Exam
NDA
Year
2012
Subject
Mathematics
Chapter
Statistics

NDA 2012 · Mathematics · Statistics

What is the standard deviation of 7,9,11,13,15 ?

What is the standard deviation of 7,9,11,13,157,9,11,13,15 ?

Options

  1. A2.4
  2. B2.5
  3. C2.7
  4. D2.8

Correct answer

D. 2.8

Step-by-step solution

S.D. =σ=1nΣ(x−xˉ)2=\sigma=\sqrt{\frac{1}{n} \Sigma(x-\bar{x})^2}=1n[16+4+4+16]=405=8&=22=2×1.4=2.8\begin{aligned} & =\sqrt{\frac{1}{n}[16+4+4+16]}=\sqrt{\frac{40}{5}}=\sqrt{8} \& =2 \sqrt{2}=2 \times 1.4=2.8 \end{aligned}$$
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