Respuesta :
The variance of each random variable is given as follows:
a) Var(2x - y) = 10.4165.
b) Var(x + 3y - 5) = 20.833.
What is the variance of random variable?
The number that occurs when each dice is thrown is represented by an uniform variable, with bounds a = 1 and b = 6, hence the variance of each variable is calculated as follows:
Var(x) = Var(y) = (6 - 1)²/12 = 2.0833.
When two variables are added, the variance is calculated as follows:
Var(aX + bY) = a²Var(X) + b²Var(Y)
Hence, for item a, the variance is calculated as follows:
Var(2x - y) = 2²Var(x) + (-1)²Var(y) = 4Var(x) + Var(y)
The variances were calculated before, which are both of 2.0833, hence:
4Var(x) + Var(y) = 4 x 2.0833 + 2.0833 = 10.4165.
For item b, the variance is calculated as follows:
Var(x + 3y - 5) = Var(x) + 3²Var(y) + (-1)²Var(-5).
The variance of a constant is of zero, hence Var(-5) = 0, and then:
Var(x + 3y - 5) = Var(x) + 3²Var(y) + (-1)²Var(-5) = 2.0833 + 9(2.0833) = 20.833.
More can be learned about variance at https://brainly.com/question/15858152
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