Mathematics · 2020
JEE Main · 8 January 2020, Shift 1 · Q67
The mean and the standard deviation (s.d.) of 10 observations are 20 and 2 respectively. Each of these 10 observations is multiplied by p and then…
The mean and the standard deviation (s.d.) of $\displaystyle 10$ observations are $\displaystyle 20$ and $\displaystyle 2$ respectively. Each of these $\displaystyle 10$ observations is multiplied by p and then reduced by q , where $\displaystyle \mathrm{p} \neq 0$ and $\displaystyle \mathrm{q} \neq 0$. If the new mean and new s.d. become half of their original values, then q is equal to :
Official answer
(4)
$\displaystyle -20$
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JEE Main 2020 Mathematics question, with the answer from NTA’s final answer key. Where our answers come from.