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October 2nd, 2017, 11:14 AM   #1
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If an increased rate of death in a population of 200 million people was noted (89% in 14 years), how many years would it take before they were all dead?

And would the percentage increase over this time, or decrease?

This is not a problem for school; it is a question I have about mortality expectancy, and I may not be presenting this correctly as I am certainly not a mathematician!

Last edited by skipjack; October 15th, 2017 at 05:24 PM.
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October 2nd, 2017, 02:40 PM   #2
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Question not clear. 89% of what? Second question can't be answered without further information.
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October 2nd, 2017, 10:32 PM   #3
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Quote:
Originally Posted by Arlynne View Post
. . . before they were all dead?
Is there a birth rate?
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October 2nd, 2017, 10:50 PM   #4
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What is the initial rate of death?
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October 3rd, 2017, 06:48 AM   #5
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Quote:
Originally Posted by Arlynne View Post
...and I may not be presenting this correctly as I am certainly not a mathematician!
Well, ask someone to help you "word" the problem correctly....
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October 15th, 2017, 12:49 PM   #6
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There is no information about the death rate that will tell you the age of death of one specific person. Deaths are similar (identical?) to independent events, which do not have guarantees. For example, you can calculate how many coins you need to flip to have a 99% chance of at least 1 head, but you can't calculate amount for a 100% chance. You cannot calculate how long until every person in a group of 200 million will be dead.
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October 15th, 2017, 03:00 PM   #7
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There is no definitive statement as to how long before everyone is dead (if ever). These models never reach 100% exactly. It's a consequence of having a death rate. Eventually the model predicts that approximately 1 person remains. What happens next? 89% (extraordinarily high, but it's your number) of that person dies? What does that mean?

Such models are usually used for long term qualitative analysis: extinction or some type of survival (often periodic); or shorter term quantative analysis (the population will reduce by x% over y years). Of course, when the predicted population is much less than 1 (0.01, say) you can be reasonably sure that they've all died, but the simplifying errors in the model itself make accurately pinpointing precise populations or when they'll happen impossible.
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