The mean and standard deviation of $20$ observations are found to be $10$ and $2$, respectively. On respectively, it was found that an observation by mistake was taken $8$ instead of $12$ . The correct standard deviation is

  • [JEE MAIN 2024]
  • A

    $\sqrt{3.86}$

  • B

    $ 1.8$

  • C

    $\sqrt{3.96}$

  • D

    $1.94$

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