Independent solution

How to solve this Deductible Payments question

Setup

Setup

Write the payment as a constant shift followed by a proportional scaling.

Y=p(Xd)=pXpdY=p(X-d)=pX-pd

Model

Model

Variance is invariant under an additive constant and is multiplied by the square of a scale factor.

Var(aX+b)=a2Var(X)\operatorname{Var}(aX+b)=a^2\operatorname{Var}(X)

Compute

Compute

Apply the affine-variance rule to the payment.

Var(Y)=p2Var(X)=p2v\operatorname{Var}(Y)=p^2\operatorname{Var}(X)=p^2v

Answer

Answer

The deductible changes the mean but not the variance; the proportional factor supplies the square.

p2v(B)\boxed{p^2v\quad\text{(B)}}