Mathematics · 2020
JEE Main · 8 January 2020, Shift 2 · Q68
The mean and variance of 20 observations are found to be 10 and 4, respectively. On rechecking, it was found that an observation 9 was incorrect and…
The mean and variance of $\displaystyle 20$ observations are found to be $\displaystyle 10$ and $\displaystyle 4$, respectively. On rechecking, it was found that an observation $\displaystyle 9$ was incorrect and the correct observation was 11. Then the correct variance is :
Official answer
(2)
$\displaystyle 3.99$
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JEE Main 2020 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.