joint distribution of 2 normal distributions isn't necessarily a normal distribution in 2 variables. Independence would be sufficient condition for that, yet obviously there is no independence between various measurements of a human body. https://en.wikipedia.org/wiki/Multivariate_normal_distributi...
When the U.S. air force discovered the flaw of averages
31–40 of 115 posts
Re: When the U.S. air force discovered the flaw of averages
#32The concept of no members of a group fitting into the average range for all observations is reminiscent of the 'curse of dimensionality'. Can anyone with a data science background make the connection here? Secondly, this seems to explain why everyone hates autocorrect.
Re: When the U.S. air force discovered the flaw of averages
#33joint distribution of 2 normal distributions isn't necessarily a normal distribution in 2 variables. Independence would be sufficient condition for that, yet obviously there is no independence between various measurements of a human body. https://en.wikipedia.org/wiki/Multivariate_normal_distributi...
"This bubble represents all pilots between 5'6" and 5'11" in height. And here's the bubble that represents those with 40" chests. Note how they barely intersect."
Re: When the U.S. air force discovered the flaw of averages
#34Earlier quoted context omitted.
That's assuming that they're independent, though, which is certainly false. I'm curious by how much.
Why is it certainly false?
Re: When the U.S. air force discovered the flaw of averages
#35Articles like this remind me how rational and practical the military is. I know so many brilliant military minds, yet war itself seems outdated and plagued by so many emotionally irrational decisions. I can't reconcile those two thoughts. How can people inside the military be so incredibly smart, yet still think it makes sense to ... you know, kill people's friends and families and not expect them to become terrorist…
These aren't just euphemisms. If you're trying to win a war solely by killing the enemy, you're going to be in for a looooong and bloody war. In fact, there's long been a thinking in the military that "a dead soldier removes one soldier from the field, but a wounded soldier removes two".
What makes the military, and war, seem "outdated" or downright "despicable" comes down to, I think, two things:
1. War is often what happens when two sides have let long lingering issues fester to the point that dialogue is not possible. In other words, the only thing anyone wants less than to throw the first punch is to be unable to throw the second.
2. Yes, military industrial complex. Specifically, the MIC has muddled the "goals" and abstracted them away behind many layers of "weapons systems" and "advanced tactics". That is, if you're a general attempting to disrupt lines of communication, and you have to decide on committing the lives of your soldiers and potentially taking the lives of your enemy, you might consider a battle plan that minimizes loss of life. If you're that same general and Raytheon (or Lockheed or Honeywell or...) offers to sell you the CommsRuptor 7000 that will take out enemy communications at the press of a button (and a signature on a check for $300M), you might not adequately question the impact on lives. War used to be about loss of blood and treasure. Lately it seems to be more about treasure and blood...
[1] Especially not the "grunts" that see front-line action. I've heard, anecdotally, that enlisted soldiers are often trained in such a way that they enter war zones with raw blood-lust. Whatever your opinion on this practice, I took from your question that you were more interested in the thinking of the decision-makers, i.e. commissioned officers.
Re: When the U.S. air force discovered the flaw of averages
#36Articles like this remind me how rational and practical the military is. I know so many brilliant military minds, yet war itself seems outdated and plagued by so many emotionally irrational decisions. I can't reconcile those two thoughts. How can people inside the military be so incredibly smart, yet still think it makes sense to ... you know, kill people's friends and families and not expect them to become terrorist…
Re: When the U.S. air force discovered the flaw of averages
#37Similarly, imputation of "race" by genome testing depends crucially on assuming that the average genome is informative, but for any trait of interest, a person who by both genome testing and known historical ancestry is categorized in some "race" category might have any degree of variance from "average" in the trait found in the whole human genome. It will be exciting to follow up on larger and larger data sets on these issues as human genomics projects continue.
Re: When the U.S. air force discovered the flaw of averages
#38Is it just me or does this sound oddly familiar to machine learning recommendation systems? ie: show an item based on the average of all the other items that everyone else has looked at.
Yeah, I was thinking of the same thing. It's not my field professionally though, so I am not sure what the relevant conclusion would be for machine learning though (or if the comparison holds at all).
Recommendation engines normally work by taking the things you favor, then looking at who else favors those things, and deducting that you're all likely to have shared interests.
Re: When the U.S. air force discovered the flaw of averages
#39The concept of no members of a group fitting into the average range for all observations is reminiscent of the 'curse of dimensionality'. Can anyone with a data science background make the connection here? Secondly, this seems to explain why everyone hates autocorrect.
Yes, this can be made precise: For example, consider a uniform distribution on a d-dimensional cube with side length 1. Only a (1/2)^d fraction of the mass is within 0.25 distance of the average in every coordinate. In high dimensions, almost all the mass is "near the boundary" in at least one coordinate.
Re: When the U.S. air force discovered the flaw of averages
#40Earlier quoted context omitted.
Do military people disagree with your analysis about killing ?
I was really dismayed when Colin Powell argued for invading Iraq. Yes, there are military people who get it. But just look what's happening. I guess they have to think, what is the alternative? We can't change our role in the Middle East. We can't just stop supporting Israel for example. I suppose yes, they tried Camp David. I guess I just want everyone to cease fire. Maybe the overpowered people resorting to terrori…
http://www.theatlantic.com/magazine/archive/2012/11/general-... for one discussion of this.