Question

13. If xy = 2638, X = 14, y = 17, n = 10 then cov (x, y) is
(A) 24.2
(B) 25.8
(C) 23.9
(D) 20.5​

Answer 1

Answer:

(B) 25.8

Step-by-step explanation:

hope it is helping..

Answer 2

Answer:

The correct answer is option (B) 25.8

Concept:

Covariance: Covariance is defined as the measure of relationship between two given variables. Suppose there is two sets of variables x and y. Their covariance is given by,

Cov(x, y) = ∑xy/n - (∑x/n)(∑y/n)

where n is the number of terms.

Given:

∑xy = 2638

X = 14 = Mean of x

Y = 17 = Mean of y

n = 10

Find:

cov(x, y) [Covariance between x and y]

Solution:

Covariance between x and y is given by,

cov(x, y) = ∑xy/n - (∑x/n)(∑y/n)

But (∑x/n) = Mean of x = X

(∑y/n) = Mean of y = Y

∴ cov (x, y) = (∑xy/n) - XY

Putting all the values in the above formula, we get

cov (x, y) = (2638/10) - (14)(17)

               = 263.8 - 238

               = 25.8

cov (x,y) = 25.8

Hence, the correct answer is option (B).

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