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I missed the part where the paradox was explained. If every woman goes from having 3 children to 2, why did the rate go up?
by ReactiveJelly 4y ago
I missed the part where the paradox was explained.
If every woman goes from having 3 children to 2, why did the rate go up?
- Strilanc 4y agoSuppose there's 1 woman who had 10 kids, and everyone else had 3. Everyone then has max kids according to the "1 fewer than mother" rule. After 5 generations that 1 woman has 10 * 9 * 8 * 7 * 6 * 5 = 151200 descendants that will each have 4 kids. Everyone else went extinct several decades ago. So the average number of children per woman increased from 3 to 4.
- Supermancho 4y ago> Everyone then has max kids according to the "1 fewer than mother" rule. 1 fewer is not the rule. The rule is "every woman has to have fewer children than her mother" There will be some whose mother had 10 then the daughter had 1. This narrative implies that every woman is having as many kids as possible all the time, which is both unrealistic and misleading by statistics. With a narrative sample size of one, the story is indicating that the number of people inevitably increased because of the rule rather than explaining this is an edge case paradox.
- cryptonector 4y agoYeah, but TFA then shows a graph of 1-fewer-than-mother.
- Supermancho 4y agoThat's the point. It's making an implicit assumption by graphing the maxima rather than demonstrating the range, making the paradox seem more likely than it is.
- cryptonector 4y agoBut after 10 generations they all go extinct.
- B1FF_PSUVM 4y agoBecause of the shape of the distribution. Those who had >= 4 were sufficiently numerous for the second generation going to 3.3. P.S. also, further iteration is not discussed. Possibly the average for that particular curve would come down on the second or third generation.
- daenz 4y agoBecause every woman didn't go from 3 to 2. The average was 3. Some families had 10 and went to 9.
- ReactiveJelly 4y agookay, I think this one made it make sense for me. Also the "Eventually it goes to zero, but at first it increases". Maybe that's what the graphs were saying, and usually I skim text and read graphs, but the graphs were confusing
- daxfohl 4y agoImagine a population of 2 women, one who has 2 children and one who has 100. Average is 51. Next generation 2 women have 1 child each and 100 women have 99 each, so the average is about 98. Eventually it will go down to zero, but initially it goes up.
- alcover 4y agoYou're supposing they bear females only ?
- deleted 4y ago[deleted]
- underwater 4y agoAnother way to look at it is to focus on the children. 99 children have a mother who had lots of children, and 2 children whose mother didn't. Basically, if you pick a child at random, they're more likely to come from a family with a lot of children. A similar paradox is the friendship paradox. On average, your friends have more friends than you do.