CT3 IFOA April 2012 Question 10

Discussion in 'CT3' started by vidhya36, Apr 22, 2015.

  1. vidhya36

    vidhya36 Very Active Member

    Q10. part (i) a) Determine the probability function of S.
    How did they arrive at the conclusion that S takes the values 0,1,2,3,4?
    Also, how the probability of P(S=3) is calculated?
    I could not understand this part... http://imgur.com/SwnQq1W
     
  2. Hemant Rupani

    Hemant Rupani Senior Member

    as per Probabilities
    Max no. of claims=2, max cars involves=2, so max S totals 4
    min is 0.

    P(S=3)=3 cars involved in accidents=P(2 accidents)[P(3 cars in 2 accidents)]
    P(2 accidents)=0.2,P(3 cars in 2 accidents)=0.7*0.3+0.3*0.7
     
  3. vidhya36

    vidhya36 Very Active Member

    Ok. Got it.
     
  4. trackr

    trackr Member

    Can someone please explain this question to me? I am really having difficulty understanding the wording of this question.

    I will try to breakdown my understanding here:

    1) The first 'table' shows that a policyholder can make 0 claims, 1 claim or 2 claims in a year. It shows probability distribution for those claims.

    2) The second 'table' tells us how many cars can be involved in each accident that results in a claim. So AM I right in saying that, if there is 1 claim, there can be 2 cars involved in the accident or 1 car. And if there are 2 claims/accidents there can be one car involved in the accident or 2 cars involved in the accident

    So S can take values of:

    0 - so that means there are no claims, hence no cars involved in each accident.
    1 - so that means there was 1 claim and 1 car was involved in the accident or 2 separate claims by a policy holder and in each claim there was 1 car involved.
    However when the solution gives P(S=1), it seems to me that they have taken P(n=1) * P(x=1). Why did they not take the other scenario of having 2 separate claims and in each claim there was 1 car involved?

    The wording is really confusing me on this one.
     
  5. Hemant Rupani

    Hemant Rupani Senior Member

    if No. of claims=2, There will be at least 2 cars involve in the total claims.
    Cars involved in first claim-second claim :1-1, 1-2, 2-1, 2-2. (Note: each accident results in a claim)

    Answer to bold fonts:
    For x=2 and n=1, S will be 2.
    P (S=2)=P (n=1) × P (x=2) + P (n=2)×P (x=1)×P (x=1) or P(one claim with 2 cars) + P(two claims with one car involve in each)
     
    trackr likes this.

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