Multiplying variances:

Suppose a variance = 2.
If you were to multiply it by 4, how would it transform it. Is it just directly multiplying it by 4, or do you have to square the 4 first?

I know you can't add variances by a constant, idk if you directly multiply them.

Formal Notation Shown Below:

Question

Multiplying variances:

Suppose a variance = 2.
If you were to multiply it by 4, how would it transform it. Is it just directly multiplying it by 4, or do you have to square the 4 first?

I know you can't add variances by a constant, idk if you directly multiply them.

Formal Notation Shown Below:

mhchen · Answer

$$\sigma ^{2}_{x} = 2~~~~~~~\sigma^{2}_{4x}=?$$

amorfide · Answer

If Var(X) = 2.5 then,

Var(2X) = 2^2 × Var(X) = 4 × 2.5 = 10

Var(4X − 3) = 4^2 × Var(X) = 16 × 2.5 = 40

so to my understanding you would do 4^2 x 2

mhchen · Answer

That's what I thought as well. ty.