Independent solution
How to solve this Deductible Payments question
Setup
Setup
Write the payment as a constant shift followed by a proportional scaling.
Model
Model
Variance is invariant under an additive constant and is multiplied by the square of a scale factor.
Compute
Compute
Apply the affine-variance rule to the payment.
Answer
Answer
The deductible changes the mean but not the variance; the proportional factor supplies the square.