Random Variables Question (1 Viewer)

[davidgoes4wce]

I didnt understand the 2nd last and 3rd last line of the working out. Anyone could give me an explanation?

 

[InteGrand]

I didnt understand the 2nd last and 3rd last line of the working out. Anyone could give me an explanation?

It's based on the properties of variance. If a is a constant and X is a random variable, remember that

Var(aX) = a² Var(X) and Var(X + a) = Var(X).

Hence if b is also a constant, we in general have

Var(a + bX) = Var(bX)

= b² Var(X).

 

[davidgoes4wce]

It's based on the properties of variance. If a is a constant and X is a random variable, remember that

Var(aX) = a² Var(X) and Var(X + a) = Var(X).

Hence if b is also a constant, we in general have

Var(a + bX) = Var(bX)

= b² Var(X).

OK thanks I get it, the 100 was chucked in there to throw us off. Its the constant next to the 'L' in this case which is affected.