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Mathematics · 2018
JEE Main 2018 · 2018-04-08 Offline · Q87
If Σ_i=1^9(x_i-5)=9 and Σ_i=1^9(x_i-5)^2=45, then the standard deviation of the 9 items x_1, x_2, ….., x_9 is:
If $\displaystyle \sum_{i=1}^9\left(x_i-5\right)=9$ and $\displaystyle \sum_{i=1}^9\left(x_i-5\right)^2=45$, then the standard deviation of the $\displaystyle 9$ items $\displaystyle x_1, x_2, \ldots . ., x_9$ is :
Official answer
(3)
$\displaystyle 2$
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JEE Main 2018 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.