CT5 Sept 2014 Q13

Discussion in 'CM1' started by Laura, Aug 21, 2021.

  1. Laura

    Laura Very Active Member

    Hi, I'm having some trouble obtaining the dependent probabilities from the independent probabilities.

    I obtain meu from each independent prob by meu=-ln(1-q_x)

    Then I use the dependent prob formula.
    However the numbers I obtain is slightly different e.g I get the following for the dependent prob of death for ages 55,56,57: 0.00473, 0.00593,0.00614
    Which is different from the answer given.

    Would you be able to explain how the answers in the examiner report are obtained?

    Thanks!
     
  2. Joe Hook

    Joe Hook ActEd Tutor Staff Member

    Hi Laura,

    I haven't managed to reconcile your answers. You can get away with a couple of approaches here. Either you multiply the qxs by 110% or the forces of mortality.

    With the former you would calculate mu55 as -ln(1-q55*1.1). Your dependent probability of death would then be:

    mu55 / (mu55 + 0.04 + 0.1) * (1 - exp(-mu55 + 0.04 + 0.1)

    With the latter you calculate mu as -ln(1-q55) and then multiply the resulting force by 110% to get mu55(*). This leads to a dependent probability of death of:

    mu55(*) / (mu55(*) + 0.04 + 0.1) * (1 - exp(-mu55(*) + 0.04 + 0.1).

    If this doesn't help, perhaps you could provide me with some more detailed calculations so I could see where things might have gone wrong.

    Thanks
    Joe
     
  3. Laura

    Laura Very Active Member

    Hi Joe, I've just tried to calculate and managed to obtain the answers in the report - might have made some calculation mistakes somewhere previously.

    Thanks Joe!
     

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