If the mean and the variance of 6,4, a, 8, b, | vedclass

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Question

$\because 	ext { mean }=9$
$	herefore 53+ a + b =72$
$\Rightarrow a + b =19$
$\because \sigma^2=\frac{37}{4} 	ext { and }(\overline{ X })^

Vedclass · Accepted Answer

$103$

Vedclass · Answer

$\because 	ext { mean }=9$
$	herefore 53+ a + b =72$
$\Rightarrow a + b =19$
$\because \sigma^2=\frac{37}{4} 	ext { and }(\overline{ X })^2+\sigma^2=\frac{\sum x _1^2}{N}$
$\Rightarrow 81+\frac{37}{4}=\frac{529+ a ^2+ b ^2}{8}$
$\Rightarrow 648+74=529+ a ^2+ b ^2$
$\Rightarrow a ^2+ b ^2=193$
$\because a + b =19 \Rightarrow a ^2+ b ^2+2 ab =361$
$\Rightarrow 2 ab =168$
$\Rightarrow ab =84$
$	herefore a + b + ab =103$

If the mean and the variance of $6,4, a, 8, b, 12,10, 13$ are $9$ and $9.25$ respectively, then $a+b+a b$ is equal to :

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