Exercise
For a two-year term insurance of 1 on (x) payable at the moment of death, you are given:
i) [math]q_{x}=0.04[/math]
ii) [math]q_{x+1}=0.06[/math]
iii) Deaths are uniformly distributed over each year of age
iv) [math]i=0.04[/math] v) [math]Z[/math] is the present value random variable for this insurance
Calculate [math]\operatorname{Var}[\mathrm{Z}][/math].
- 0.065
- 0.069
- 0.073
- 0.077
- 0.081
Answer: E
[math]E(Z)=\frac{i}{\delta}\left[v q_{x}+v^{2} p_{x} q_{x+1}\right]=\frac{0.04}{\ln (1.04)}\left[\frac{1}{1.04}(0.04)+\frac{1}{1.04^{2}}(0.96)(0.06)\right]=0.09353831[/math]
[math]E\left(Z^{2}\right)=\frac{(1+i)^{2}-1}{2 \delta}\left[v^{2} q_{x}+v^{4} p_{x} q_{x+1}\right]=\frac{\left(1.04^{2}-1\right)}{2 \ln (1.04)}\left[\frac{1}{1.04^{2}}(0.04)+\frac{1}{1.04^{4}}(0.96)(0.06)\right]=0.08969072[/math]
[math]\operatorname{Var}(Z)=E\left(Z^{2}\right)-[E(Z)]^{2}=0.08969072-(0.09353831)^{2}=0.0809413[/math]