CM1B Sept 2021 Q1 i)

Discussion in 'CM1' started by Abbie, Mar 19, 2024.

  1. Abbie

    Abbie Made first post

    Hi,
    Please could you explain the difference between the columns labelled P(death in month) and 1/12qx in the solution spreadsheet?
    I thought that 1/12qx is the probability of a life aged x dying in the next month, so I'm not sure how that's different to the probability of death in the month?
    Thanks
     
  2. Joe Hook

    Joe Hook ActEd Tutor Staff Member

    Hi,

    A qx probability is the probability a life dies over the next period GIVEN they were alive at the start of the period.

    The probability of death in month here is working out the probability that the life dies in a particular month GIVEN they were alive at the start of the year. It could be calculate as the probability the life survives to the start of the month multiplied by the qx for that month or as in this case it can be calculated as the difference between 2 survival probabilities.

    eg If there's a 90% chance I survive from now until June and an 85% chance I survive from now until July then there must be a 5% chance I die between June and July.

    Hope this helps.
    Joe
     
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