Let X represent the number that occurs when a red die is tossed and Y the number that occurs when a green die is tossed. Find (a) E(X + Y ); (b) E(X

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Answer:

Step-by-step explanation:

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The expressions of red die, and green die are illustrations of expected values

We have the following parameters from the complete question

[tex]E(X) = \frac 72[/tex]

[tex]E(Y) = \frac 72[/tex]

(a) Calculate E(X + Y)

Since X and Y are independent random variables, then

[tex]E(X + Y) = E(X) + E(Y)[/tex]

So, we have:

[tex]E(X + Y) = \frac 72 + \frac 72[/tex]

Take LCM

[tex]E(X + Y) = \frac{7+ 7}2[/tex]

Add 7 and 7

[tex]E(X + Y) = \frac{14}2[/tex]

Divide 14 by 2

[tex]E(X + Y) = 7[/tex]

Hence, the value of E(X + Y) is 7/2

(b) Calculate E(X - Y)

Since X and Y are independent random variables, then

[tex]E(X - Y) = E(X) - E(Y)[/tex]

So, we have:

[tex]E(X - Y) = \frac 72 - \frac 72[/tex]

Take LCM

[tex]E(X - Y) = \frac{7- 7}2[/tex]

Subtract 7 from 7

[tex]E(X - Y) = \frac{0}2[/tex]

Divide 0 by 2

[tex]E(X + Y) = 0[/tex]

(b) Calculate E(X - Y)

Since X and Y are independent random variables, then

[tex]E(X - Y) = E(X) - E(Y)[/tex]

So, we have:

[tex]E(X - Y) = \frac 72 - \frac 72[/tex]

Take LCM

[tex]E(X - Y) = \frac{7- 7}2[/tex]

Subtract 7 from 7

[tex]E(X - Y) = \frac{0}2[/tex]

Divide 0 by 2

[tex]E(X - Y) = 0[/tex]

Hence, the value of E(X - Y) is 0

(c) Calculate E(XY)

Since X and Y are independent random variables, then

[tex]E(X Y) = E(X) \times E(Y)[/tex]

So, we have:

[tex]E(XY) = \frac 72 \times \frac 72[/tex]

Multiply

[tex]E(XY) = \frac{49}4[/tex]

Hence, the value of E(XY) is 0

Read more about expected values at:

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