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NDA 2019
Exam
NDA
Year
2019
Subject
Mathematics
Chapter
Statistics

NDA 2019 · Mathematics · Statistics

The mean of 5 observations is 4.4 and variance is 8.24. If three of...

The mean of 5 observations is 4.4 and variance is 8.24. If three of the five observations are 1,2 and 6, then what are the other two observations?

Options

  1. A9,16
  2. B9,4
  3. C81,16
  4. D81,4

Correct answer

B. 9,4

Step-by-step solution

Given: n=5n=5xˉ=4.4σ2=8.24∵Σx=xˉ⋅x⇒Σx=5×4.4=22 also 1+2+6+p+q=22⇒p+q=13∴9,4=p,q.\begin{aligned} & \bar{x}=4.4 \\ & \sigma^2=8.24 \\ & \because \quad \Sigma x=\bar{x} \cdot x \\ & \Rightarrow \quad \Sigma x=5 \times 4.4=22 \\ & \text{ also } 1+2+6+p+q=22 \\ & \Rightarrow p+q=13 \\ & \therefore \quad 9,4=p, q . \end{aligned}$$
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