3 ms·

>An event for which the timing is unpredictable may "at this time" have only a 5-percent probability of occurring during the coming month, but a 60-percent prob

>An event for which the timing is unpredictable may "at this time" have only a 5-percent probability of occurring during the coming month, but a 60-percent probability if the time frame is extended to one year (5 percent per month for 12 months). If the time frame were extended to two years, would the probability be 120%? The correct probability is: 1 - (1-.05)^12 ~= 0.46 Hard to credit a text about cognitive biases that makes elementary mistakes in probability.

bane 9y ago
You may have knowledge that the probability falls to zero after that. This is messy intelligence not math. Assuming this is a math book is a cognitive bias you are bringing into the reading.
- _benedict 9y ago
  The quoted text specifically refers to this being the result of a 5% monthly chance recurring over 12-months, i.e. it was a pretty unambiguous appeal to mathematics. Whether or not it is reasonable to compound such a messy probability is a whole other question, but the fact the training material could not do so correctly (on apparently its own terms) does not speak with great confidence for the practitioners trained upon it.
  - cirgue 9y ago
    > The quoted text specifically refers to this being the result of a 5% monthly chance recurring over 12-months, i.e. it was a pretty unambiguous appeal to mathematics. No it isn't. If I have some information about events that will occur over the next few months, my estimations will be different based on that knowledge, eg I know there is going to be an election in some neighboring country that will involve violence, so I think that the probability of being unable to ship overland through that country is low now, but high in a few months.
    - _benedict 9y ago
      Have you read the quote? "5 percent per month for 12 months" I don't know how to reconcile this with your interpretation.
      - cirgue 9y ago
        My bad, I thought that was added by the parent.
Bartweiss 9y ago
Doesn't this depend on whether the event can recur? Your math correctly assess the odds of a one time event, as one minus the odds of the event never occurring. But if 5%/month is an expected frequency of a recurring event, then after 24 months we'd expect 1.2 occurrences. Yeah? edit: Their language is awfully sloppy, though. It's not a 60% chance in the next 12 months, it's .6 expected occurrences.

bane 9y ago

You may have knowledge that the probability falls to zero after that. This is messy intelligence not math. Assuming this is a math book is a cognitive bias you are bringing into the reading.

_benedict 9y ago
The quoted text specifically refers to this being the result of a 5% monthly chance recurring over 12-months, i.e. it was a pretty unambiguous appeal to mathematics. Whether or not it is reasonable to compound such a messy probability is a whole other question, but the fact the training material could not do so correctly (on apparently its own terms) does not speak with great confidence for the practitioners trained upon it.
- cirgue 9y ago
  > The quoted text specifically refers to this being the result of a 5% monthly chance recurring over 12-months, i.e. it was a pretty unambiguous appeal to mathematics. No it isn't. If I have some information about events that will occur over the next few months, my estimations will be different based on that knowledge, eg I know there is going to be an election in some neighboring country that will involve violence, so I think that the probability of being unable to ship overland through that country is low now, but high in a few months.
  - _benedict 9y ago
    Have you read the quote? "5 percent per month for 12 months" I don't know how to reconcile this with your interpretation.
    - cirgue 9y ago
      My bad, I thought that was added by the parent.

Bartweiss 9y ago

Doesn't this depend on whether the event can recur? Your math correctly assess the odds of a one time event, as one minus the odds of the event never occurring. But if 5%/month is an expected frequency of a recurring event, then after 24 months we'd expect 1.2 occurrences. Yeah? edit: Their language is awfully sloppy, though. It's not a 60% chance in the next 12 months, it's .6 expected occurrences.