In an experiment with 15 observations on $x$, we have $\sum x^2=2830, \sum x=170$. One observation that was 20 was found to be wrong and was replaced by the correct value 30 , then the corrected variance is

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Aicharya · Accepted Answer

$\begin{aligned} & 	ext { Correct variance }=\frac{\sum x^2-20^2+30^2}{15}-\left(\frac{\sum x-20+30}{15}ight)^2 \ & =\frac{2830-400+90}{15}-\left(\frac{170-20+30}{15}ight)^2 \ & =222-144=78\end{aligned}$

In an experiment with 15 observations on $x$, we have $\sum x^2=2830, \sum x=170$. One observation that was…

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