Course 4 Actex: Practice Exam I, problem 23

[New at pd]

Hi everyone,
It appears as if the solution this problem uses 2 deaths at time 3 rather than 6 deaths, as described in the problem. There are 2 observations that are censored at this time, but that has nothing to do with calculating the Nelson-Aalen estimator, except in determining the risk set at a particular time. Am I right in saying that this is an error? Any ideas are greatly appreciated.

[Higher Authority]

In my actex the above problem is for question 24. However I believe that there is an error on problem 23 test 1.
"The number of claims per period has a Bernoulli distribution with mean ^ . the parameter ^ has a uniform distribution on the interval (0,T). the parameter T has apdf h(T) = 2t for 0<t<1. Find P[N=0]. my answer was D) 2/3. This was also supported using a simulation in excess of 800 numbers.



<font size=-1>[ This Message was edited by: Needo on 2001-09-12 13:31 ]</font>

[New at pd]

I meant #24.

What do you think is wrong with 23?

[Higher Authority]

In reply to the first post.
H~(3)=4/50+4/44+6/37=.333 following the same correction through the problem the ultimate answer should be E).21 . If you didn't drop any decimals you should have a solution of .213847.

[Higher Authority]

on question#24 I did a simulation and solved the question using the expectation of the parameter ^. And by both methods, I came up with a solution of 2/3 for the probability that N=0.

Furthermore in the seccond to the last line of the solution we have g(^)=2(1-^) the 2 is droped in the last line.




<font size=-1>[ This Message was edited by: Needo on 2001-09-12 14:36 ]</font>