Variance of α , β and gamma is 9 , then variance of 5 α , 5 β and 5 gamma is

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The variance of $\alpha$, $\beta$ and $\gamma$ is $9$, then variance of $5$$\alpha$, $5$$\beta$ and $5$$\gamma$ is

A

$45$

B

$9\over5$

C

$5\over9$

D

$225$

Solution

(d) When each item of a data is multiplied by $\lambda $, variance is multiplied by ${\lambda ^2}$.

Hence, new variance $ = {5^2} \times 9$$ = 225$.

Standard 11

Mathematics

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