If Sigma x=15, Sigma y=40, Sigma xy=110 and n=5, then the value of cov (x,y) is

Question

If Sigma x=15, Sigma y=40, Sigma xy=110 and n=5, then the value of cov (x,y) is (A)  -2  (B) 2 (C) 22 (D) None of these

Tardigrade Admin · Accepted Answer

Given, Sigma x=15, text Sigma y=40, text Sigma xy=110, text n=5 overlineX=(1/n) Sigma x=(1/5)× 15=3 overlineY=(1/n) Sigma y =(1/5)× 40=8 operatornamecov(x,y)=(1/n) Sigma xy- overlineX overlineY =(1/5)× 110-3× 8 =22-24=-2

Q. If $Σ x = 15, Σ y = 40, Σ x y = 110$ and $n = 5,$ then the value of cov $(x, y)$ is

$- 2$

2

22

None of these

Given, $Σ x = 15, Σ y = 40, Σ x y = 110, n = 5$
$\overline{X} = \frac{1}{n} Σ x = \frac{1}{5} \times 15 = 3$
$\overline{Y} = \frac{1}{n} Σ y$ $= \frac{1}{5} \times 40 = 8$
$cov (x, y) = \frac{1}{n} Σ x y - \overline{X} \overline{Y}$
$= \frac{1}{5} \times 110 - 3 \times 8$
$= 22 - 24 = - 2$

Q. If Σx=15,Σy=40,Σxy=110 and n=5, then the value of cov (x,y) is

−2

2

22

None of these

Given, Σx=15,Σy=40,Σxy=110,n=5 X=n1​Σx=51​×15=3 Y=n1​Σy =51​×40=8 cov(x,y)=n1​Σxy−XY =51​×110−3×8 =22−24=−2

Q. If $Σ x = 15, Σ y = 40, Σ x y = 110$ and $n = 5,$ then the value of cov $(x, y)$ is

$- 2$

Given, $Σ x = 15, Σ y = 40, Σ x y = 110, n = 5$
$\overline{X} = \frac{1}{n} Σ x = \frac{1}{5} \times 15 = 3$
$\overline{Y} = \frac{1}{n} Σ y$ $= \frac{1}{5} \times 40 = 8$
$cov (x, y) = \frac{1}{n} Σ x y - \overline{X} \overline{Y}$
$= \frac{1}{5} \times 110 - 3 \times 8$
$= 22 - 24 = - 2$