May 08'23
Exercise
The probability of [math]x[/math] losses occurring in year 1 is [math]0.5x[/math] for [math]x=0,1, 2,\ldots[/math]. The probability of [math]y[/math] losses in year 2 given [math]x[/math] losses in year 1 is given by the table:
Number of losses in year 1 (x) | Number of losses in year 2 (y) given x losses in year 1 | ||||
0 | 1 | 2 | 3 | 4+ | |
0 | 0.60 | 0.25 | 0.05 | 0.05 | 0.05 |
1 | 0.45 | 0.30 | 0.10 | 0.10 | 0.05 |
2 | 0.25 | 0.30 | 0.20 | 0.20 | 0.05 |
3 | 0.15 | 0.20 | 0.20 | 0.30 | 0.15 |
4+ | 0.05 | 0.15 | 0.25 | 0.35 | 0.20 |
Calculate the probability of exactly 2 losses in 2 years.
- 0.025
- 0.031
- 0.075
- 0.100
- 0.131
May 08'23
Solution: E
[[math]]
\begin{align*}
P( x= 1, y= 1)= P( y= 1| x= 1) P( x= 1)= 0.3(0.5)^2= 0.0753 \\
P(x= 2, y= 0)= P(y= 0| x= 2) P(x= 2)= 0.25(0.5)^3=0.03125 \\
P(x=0,y=2) = P(y=2 | x = 0 ) P(x=0) = 0.05(0.5)^1 = 0.025
\end{align*}
[[/math]]
The total is 0.13125.