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The coefficient of correlation between $x$ and $y$ is $0.5$ and their covariance is $16$ and SD of $x$ is $4$ then SD of $y$ is
$\begin {array} {1 1} (A)\;4 & \quad (B)\;8 \\ (C)\;16 & \quad (D)\;64 \end {array}$
jeemain
math
cbse
class11
statistics
medium
variance-and-standard-deviation
q42
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asked
Jan 28, 2014
by
thanvigandhi_1
retagged
Sep 8, 2014
by
sharmaaparna1
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1 Answer
Given $ r = 0.5$
$cov (x,y)=16$
$ \sigma_x=4$
$ \sigma_y = \large\frac{cov (x,y)}{r\: \sigma_x}$
$ = \large\frac{16}{0.5 \times 4}$
$ = \large\frac{16}{\large\frac{1}{\not{2}} \times \not{4}2} = \large\frac{16}{2}$
$ = 8$
Ans : (B)
answered
Jan 28, 2014
by
thanvigandhi_1
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