
#451




Quote:
iii) says that each individual has an independent 80% probability of its q being 0.2 and a 20% probability of its q being 0.05. Thus, by mixing, each individual has a probability 0.8 (0.2) + (0.2) (0.05) =0.17 of death, and there are 1000 such individuals, so the number of deaths is Binomial with parameters 1000 and 0.17. So the mean and variance just come from this Binomial.
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Jim Daniel Jim Daniel's Actuarial Seminars www.actuarialseminars.com jimdaniel@actuarialseminars.com 
#452




Wow, that actually makes perfect sense. I'm going to check out that study note. I really appreciate it, I just know there's going to be a question like this on the exam
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FA And NUH is the letter I use to spell Nutches Who live in small caves, known as Nitches, for hutches, These Nutches have troubles, the biggest of which is the fact there are many more Nutches than Nitches. 
#453




Quote:
I think about it like this: The scenario in b(ii) has five total groups of 1000 each. In four of those five groups, everyone has q=.20. In the other one, everyone has q=.05. The scenario in b(iii) is one group of 1000. 80% of the 1000 have q=.20 and the other 20% has q=.05. Hope this helps.  Side note  Are we allowed to use pens on the written answer? Obviously not on the MC, but the WA? Last edited by Steveo1794; Yesterday at 07:40 PM.. 
#454




Both of Steveo1794's interpretations are incorrect.
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Jim Daniel Jim Daniel's Actuarial Seminars www.actuarialseminars.com jimdaniel@actuarialseminars.com 
#455




I wasn't referring to the literal scenarios presented in the problem, I was referring to how to distinguish between the "each subject will have" and "any given subject". That phrasing confused me, and thinking about it like that helps me.
Does the below explanation make sense? If not, please correct it. Scenario b(ii) is 80% chance that 100% of the cohort will have q=.20 and a 20% chance that 100% of the cohort will have q=.05. Scenario b(iii) is simply an 80% chance of a member of the cohort having q=.20 and a 20% chance of someone in the same cohort having q=.05.
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#456




Quote:
Your explanation of b(ii) is correct. Your explanation of b(iii) may be correct, but the wording strikes me as a little confusing. It would be clearer to say: For each member of the cohort, there is an 80% chance that that member's q is 0.2 and a 20% chance that that member's q is 0.05, and the results are independent from member to member. By the way, I agree that the exam problem as stated is poorly worded, with the "any given subject" and "each subject" difficult to distinguishand imagine what it's like for nonnative English speakers! Of course, exam questions are often poorly worded, and it's not all that rare for them to use textbook terms to mean something different from their meaning in the textbook, or to be missing data, or for the wrong answer to be considered correct. Quality control truly sucks. Candidates need to be robust problem solvers in that the first part of the problem is to figure out what the problem really is.
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Jim Daniel Jim Daniel's Actuarial Seminars www.actuarialseminars.com jimdaniel@actuarialseminars.com 
#457




The Written Answer instructions at the beginning of the exam state " Do not write answers to more than one question per sheet".
Does this mean every part (a, b, and c) to question 1, must be on an individual sheet? Or, is it okay to answer parts a, b, and c all on the same sheet? 
#458




Quote:
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FA And NUH is the letter I use to spell Nutches Who live in small caves, known as Nitches, for hutches, These Nutches have troubles, the biggest of which is the fact there are many more Nutches than Nitches. 
#459




Quote:
Hope that this help.
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