JEE PYQ: Statistics Question 11
Question 11 - 2020 (03 Sep Shift 2)
Let $x_i$ $(1 \leq i \leq 10)$ be ten observations of a random variable $X$. If $\sum_{i=1}^{10}(x_i - p) = 3$ and $\sum_{i=1}^{10}(x_i - p)^2 = 9$ where $0 \neq p \in \mathbb{R}$, then the standard deviation of these observations is:
(1) $\sqrt{\frac{3}{5}}$ (2) $\frac{4}{5}$ (3) $\frac{9}{10}$ (4) $\frac{7}{10}$
Show Answer
Answer: (3) $\frac{9}{10}$
Solution
S.D. $= \sqrt{\frac{9}{10} - \frac{9}{100}} = \frac{9}{10}$.
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