Timeline for Expected number of ratio of girls vs boys birth
Current License: CC BY-SA 3.0
10 events
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| Apr 15, 2014 at 20:09 | comment | added | whuber♦ | @Richard Yes, that's Tim's approach, too. I am happy with how well it clarifies his (and your) sense of independence; that simple construction provides nice intuition. (At this point I have upvoted both your answers...) | |
| Apr 15, 2014 at 20:06 | comment | added | Richard Tingle | @whuber the girl-girl sequences turn up if you put all births in a line; after one couple finishs the next go in etc etc | |
| Apr 15, 2014 at 19:34 | history | edited | Tim S. | CC BY-SA 3.0 |
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| Apr 15, 2014 at 19:29 | comment | added | Tim S. | @whuber The events are independent in the same way coin flips are. I've expounded on this in my answer. | |
| Apr 15, 2014 at 19:26 | history | edited | Tim S. | CC BY-SA 3.0 |
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| Apr 15, 2014 at 16:47 | comment | added | whuber♦ | You will need to be much clearer about that. I mentioned the sequences to demonstrate the lack of independence, so the burden is on you to state exactly in what rigorous sense "independence" applies here. | |
| Apr 15, 2014 at 16:42 | comment | added | Tim S. | @whuber We're not asked how many girl-girl sequences there are. Only the ratio of girls to boys. I did not state that the sequence of births by an individual mother is a series of independent events, like coin flips. Only that each birth, individually, is an independent event. | |
| Apr 15, 2014 at 16:39 | comment | added | whuber♦ | As stated, this is incorrect. If the genders were unconditionally independent, in the long run there would be as many girl-girl sequences in births among the families as there are boy-boy-sequences. There are many of the latter and never any of the former. There is a form of independence, but it is conditional on birth order. | |
| Apr 15, 2014 at 14:15 | review | First posts | |||
| Apr 15, 2014 at 14:28 | |||||
| Apr 15, 2014 at 13:56 | history | answered | Tim S. | CC BY-SA 3.0 |