Friday, January 02, 2009

Re: Palin rumors; among pregnant, older women more likely to have Down baby than teens are

++Addition++Commenter Gullydale does the math:
In 2006 there were a total of 4,265,996 births, 15-19 year olds gave birth to 435,427 babies. 40-44 year olds gave birth to 105,476 babies. By Bayes Theorem (using 1/1250 and 1/45 as the odds), given that we know that a child has down syndrome, the probability that the mother was 40-44 is 43% and that the mother was 15-19 is 6%.
So, even taking into account the fact that a woman Bristol's age is more likely to be impregnated than someone Sarah's age is, women of Sarah's age range are more than six times as likely to have Down babies are girls Bristol's age are to have them.

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Half Sigma's 'conspiracy theorizing' about Sarah Palin playing the birth of her grandson off as her own needs to address one crucial statistical tendency arguing strongly against it--babies with Down Syndrome are more than an order of magnitude more likely to be born to women in their forties than they are to be born to teenage girls. This table shows that one in forty births to a woman Sarah's age (44) will be Down babies. In contrast, only one in 1,250 births to girls daughter Bristol's age (18) will be. So Sarah is more than 30 times as likely to have had a baby with Down's Syndrome than Bristol is.

As HS' case is built on lots of suggestive circumstantial evidence, he should at least address the improbability (not the impossibility, of course) of Sarah Palin not being the mother of the Down baby.

11 comments:

Anonymous said...

From Wikipedia:
http://en.wikipedia.org/wiki/Down_syndrome

"Although the probability increases with maternal age, 80% of children with Down syndrome are born to women under the age of 35,[15] reflecting the overall fertility of that age group."

popularsymbolism said...

'Conspiracy theories' are almost like a blanket word covering everything that the mass media regards to be ridiculous, far-fetched, etc.

When in fact, conspiracies have happened in the past, and indeed still happen to this day, and theories are the very basis for scientific facts.

It's like Orwellian Newspeak: instead of the word 'negro', we have the 'N-word', instead of using a word like 'fuck', we have the 'F-word'; for something that is considered nonsense, we have the 'conspiracy theory' word.

Just like 'thought crime' in 1984 covered everything from offensible crimes, from 'sexual perversion' to 'resistance to authority, so too does the word 'conspiracy theory'.

Anyway, this whole post is unrelated to Palin - my issue was with the word being employed as a 'knee-jerk response' to everything.

Peter said...

It's like Orwellian Newspeak: instead of the word 'negro', we have the 'N-word'

It's not "negro" for which the "N-word" is used as a euphemism.

popularsymbolism said...

Peter: I know that - I deliberately refrained from inputting the word, since it is known as a derogatory connotation.

Anyway, I'm sure you get the point I was trying to make.

popularsymbolism said...

derogatory connotation = derogatory word

Audacious Epigone said...

Anon,

That doesn't change the likelihood of either Sarah Palin or her daughter having a Down child. I suppose it could be argued that, given her age, Sarah was less likely to become pregnant than her daughter was, though.

PS,

I actually thought about just that when writing the post. I used conspiracy theory because that's what HS uses in one of his most recent posts on the subject (and the one that I linked to). But as someone interested in the realities of human biodiversity who tries to be as data-driven as possible, I try to refrain from using such loaded jargon. I've updated the post to reflect that.

Audacious Epigone said...

Anon,

Ah, I see how the post's title is technically incorrect. I've changed it, too. Thanks.

popularsymbolism said...

Audacious:

Yeah, I looked at the original article and realized where the term came from - my post wasn't a critique of your usage of it, but more or less a general observation.

As an European, and looking at US television, US television and popular discourse seems far more restricted in terms of what is considered proportional language (in most European countries, swearwords are not even censored or bleeped out). That doesn't mean this is necessarily preferable or better - swearing does not make for intelligent discourse, after all - but it does strike me as ridiculous how many euphemisms are used in the name of political correctness.

Gullydale said...

In 2006 there were a total of 4,265,996 births, 15-19 year olds gave birth to 435,427 babies
40-44 year olds gave birth to 105,476 babies

By Bayes Theorem (using 1/1250 and 1/45 as the odds), given that we know that a child has down syndrome, the probability that the mother was 40-44 is 43% and that the mother was 15-19 is 6%

Half Sigma said...

This doesn't prove anything. Bristol can give birth to a Down Syndrome baby. And she's a lot more likely to get pregnant if she's a slut and Sarah wasn't trying to get pregnant. (I'm sure the majority of 40-44 pregnancies are intentional pregnancies.)

Were it not for the Down Syndrome baby, it would have been easy to give a baby up for adoption, so the existence of a Down Syndrome baby is a prerequisite for the whole fake pregnancy scheme in the first place.

Audacious Epigone said...

HS,

If the Palin's already had four children, why do you presume the fifth was unintentional?