If x and y are two random variables then E3x 3y OA 3E3 D Ey

If x and y are two random variables, then E(3x + 3y) OA. 3E)+3 D, E(y)

Solution

1.

By linearity,

E(ax + by) = aE(x) + bE(y)

Thus,

E(3x + 3y) = 3E(x) + 3E(y) [ANSWER, B]

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2.

Note that the expectation of a product is also the product of the expectations.

Thus,

E(3x*3y) = E(3x)E(3y)

=[3E(x)][3E(y)]

=9E(x)E(y) [ANSWER, B]