Question

In: Statistics and Probability

Let X and Y be independent random variables with mean πœ‡X and πœ‡π‘Œ, and variances πœŽπ‘‹ 2 and πœŽπ‘Œ 2 respectively

 

Let X and Y be independent random variables with mean πœ‡X and πœ‡π‘Œ, and variances πœŽπ‘‹ 2 and πœŽπ‘Œ 2 respectively. Show that

π‘‰π‘Žπ‘Ÿ[𝑋 βˆ™ π‘Œ] = πœŽπ‘‹ 2 βˆ™ πœŽπ‘Œ 2 + πœ‡π‘Œ 2 βˆ™ πœŽπ‘‹ 2 + πœ‡π‘‹ 2 βˆ™ πœŽπ‘Œ 2

Solutions

Expert Solution

GIVEN:

Let X and Y be independent random variables with mean and , and variances and respectively.

TO PROVE:

PROOF:

Given the mean of X

Variance of X

The formula for variance is given by,

Given the mean of Y

Variance of Y

The formula for variance is given by,

Thus we have ; ; ; ; and .

First, we compute the mean of XY,

{Since X and Y are independent.}

Β Β 

Now the formula for variance of XY is given by,

{Since X and Y are independent and .}

Β Β 

Using and , we obtain the result,

Thus .


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