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Question: Answered & Verified by Expert
Let $\mathrm{x}_1, \mathrm{x}_2, \ldots, \mathrm{x}_{\mathrm{n}}$ be $\mathrm{n}$ observations such that $\sum \mathrm{x}_{\mathrm{i}}^2=400$ and $\sum \mathrm{x}_{\mathrm{i}}=80$. Then a possible value of $\mathrm{n}$ among the following is
MathematicsStatisticsJEE MainJEE Main 2005
Options:
  • A
    15
  • B
    18
  • C
    9
  • D
    12
Solution:
2296 Upvotes Verified Answer
The correct answer is:
18
$$
\begin{aligned}
& \frac{\sum x_i^2}{n} \geq\left(\frac{\sum x_i}{n}\right)^2 \\
& \Rightarrow n \geq 16
\end{aligned}
$$

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