Mathematics · 2021
JEE Main · 26 August 2021, Shift 1 · Q80
The mean and standard deviation of 20 observations were calculated as 10 and 2.5 respectively. It was found that by mistake one data value was taken…
The mean and standard deviation of $\displaystyle 20$ observations were calculated as $\displaystyle 10$ and $\displaystyle 2.5$ respectively. It was found that by mistake one data value was taken as $\displaystyle 25$ instead of $\displaystyle 35$ . If $\displaystyle \alpha$ and $\displaystyle \sqrt{\beta}$ are the mean and standard deviation respectively for correct data, then $\displaystyle (\alpha, \beta)$ is :
Official answer
(3)
$\displaystyle (10.5,26)$
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JEE Main 2021 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.