Independent solution

How to solve this Exponential Distribution question

Setup

Setup

Represent the insurer payment as the positive excess above the deductible.

Y=(X3)+,XExponential(mean 10)Y=(X-3)_+,\qquad X\sim\operatorname{Exponential}\left(\text{mean }10\right)

Model

Model

A positive payment requires survival beyond three, and the exponential residual loss then has its original mean.

Pr(X>3)=e3/10\Pr(X>3)=e^{-3/10}
E[X3X>3]=10\operatorname{E}[X-3\mid X>3]=10

Compute

Compute

Multiply the payment probability by the conditional mean payment.

E[Y]=e3/10(10)=7.408182207\operatorname{E}[Y]=e^{-3/10}(10)=7.408182207

Answer

Answer

The expected claim payment is approximately 7.41.

7.41(D)\boxed{7.41\quad\text{(D)}}