Alex Plank--What the @#$% is this crap?

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I agree with the first part. In the second part the math is completely wrong. You interpreted "1 in 54" as "54 of the 88" and miscalculated the math from there.

NONONONONONO! Bad Dirtdigger! No math for you! If 1/88 people had had autism and the rates are the same than 1/88 boys have autism and 1/88 girls.

Now it's time to do some REAL math. Frequency is essentially the same as probability. The rest is between 0 and 1, 0 means no one and 1 means everyone. 1 in 5 is 1/5, if the top number is larger compared to another ration with the same bottom it's more frequent, if the bottom is larger it's less fequent. To calculate the frequency in a particular group you need to divide those in the group with the condition by the total amount of people in the group. Frequency of people with autism (FP[A]) is People with autism (P[A]) divided by everyone (P), so FP[A] = P[A]/P. Likewise, for boys FB[A] = B[A]/B, and for girls FG[A] = G[A]/G. For the Sake of the problem everyone is either a boy or a girl, so P = B + G and P[A] = B[A] + G[A]. Using basic algebra by multiplying FP[A] by P you get P[A].

For our first problem, let's assume FP[A] = 1/88 and FB[A] = FG[A]. Let's call that number x. Using math we can get that P[A] = B[A] + G[A] = xB + xG = x(B + G) = xP, x = xP/P = P[A]/P = FP[A] = 1/88. Thus 1 in 88 boys would have autism, and 1 in 88 girls would have autism.

Now let's solve for FG[A] assuming FB[A] = 1/55 (the math is easier with 1/55 than 1/54) and FP[A] = 1/88. Now, to calculate the frequency of being both a girl and having autism (FP[G&A]) we use G[A]/P. G[A] is the same as G&A which is the same A&G which is the same as A[G]. To get G[A]/P we just need (P[A]/P) - (B[A]/P], which is FP[A] - FP[B&A]. FP[B&A] = FB[A] * (B/P), and FG[A] = FP[G&A]/(G/P) = (FP[A] - FP[B&A])/(G/P) = [(P/88) - P(FB[A]*[B/P])]/G = ([P/88] - [B/55])/G = (P/88G) - (B/55G). If we assume B = G then P = 2G so FG[A] = (2/88) - (1/55) = (1/44) - (1/55) = (1/[4 * 11]) - (1/[5 * 11]) = (5/[ 4 * 5 * 11]) - (4/[ 4 * 5 * 11]) = (5 - 4)/220 = 1/220. Thus approximately 1 in 220 girls has autism. I believe that actual number is far higher, but whatever.

Now let's solve for FG[A] assuming FB[A] = 1/55 (the math is easier with 1/55 than 1/54) and FP[A] = 1/88. Now, to calculate the frequency of being both a girl and having autism (FP[G&A]) we use G[A]/P. G[A] is the same as G&A which is the same A&G which is the same as A[G]. To get G[A]/P we just need (P[A]/P) - (B[A]/P], which is FP[A] - FP[B&A]. FP[B&A] = FB[A] * (B/P), and FG[A] = FP[G&A]/(G/P) = (FP[A] - FP[B&A])/(G/P) = [(P/88) - P(FB[A]*[B/P])]/G = ([P/88] - [B/55])/G = (P/88G) - (B/55G). If we assume B = G then P = 2G so FG[A] = (2/88) - (1/55) = (1/44) - (1/55) = (1/[4 * 11]) - (1/[5 * 11]) = (5/[ 4 * 5 * 11]) - (4/[ 4 * 5 * 11]) = (5 - 4)/220 = 1/220. Thus approximately 1 in 220 girls has autism. I believe that actual number is far higher, but whatever.

Thank you. I made a very stupid error when I did my calculations, which is pretty much typical for me when trying to do math. But I am happy to see that I understood the principal of what I was supposed to do.

Another fool that is quick to judge and lack the understanding who haven't read all of my posts including the article. I'm not taking the blame for this crap in this article. And knock off the math crap too. I know I'm not good in math so quit throwing it up in my face!. So of you people who pride yourselves in going in for the kill when there is a weakness shows just how unsympathic, with no empathy what so ever you are. I'm only generalizing as if there were 44 boys and 44 girls.

I MADE D'S AND F'S IN MATH. ARE YOU HAPPY NOW?

If this article gave us the right information in the first place there wouldn't be so much confusion and so many heated dabates to the point where some are picking on others once they uncover their weaknesses.

The article has absolutely nothing to do with how to calculate the figures. If you were so bad at math then why did you go ahead and be so arrogant with proclaiming your mathematical abilities and insult other people when they point out your math makes no sense? The statistic isn't worded badly, that's how they always word things and it really makes perfect sense.

Although the post was directed at you, I doubt it was a personal attack on you. (I am aware that sentence makes no sense, btw). I think, rather, it was a reaction to not following the "rules" of math, and the reaction would have been the same no matter who posted the error. I think many people here would not have been able to explain how to get the right number, hence the reason no one did it until 6 pages in. The fact that you had difficulty in math clearly explains why you made your error. I do not mean that in a derogatory way at all. The math required to do it is not "straightforward," so of course someone who doesn't have math as a strength would not do it correctly. Nothing to feel bad about.

I would imagine if he would have seen my straightforward request for help before he saw your error, he probably would have responded to that. But if he is like me, when he saw the error, he immediately wanted to correct it, not because of who made the error, and not to pick anyone apart, but because the error was made.

I hope the OP realizes that Alex designed this site.

It is acceptable, you are just being ridiculous. Be thankful that English lacks true grammatical gender. This is why feminists aren't being taken seriously.

The word "he" is often used instead of repetitively using "he or she" etc. I highly doubt any offense was meant by it.
I'm female, too.

No, in this case the author clearly just ment the boys, because so far I'm informend 1 in 54 boys is diagnosed and 1 in 88 children. So the numbers differ and the author is refering to the number of boys diagnosed and continues with "he".