Either the left handed really perform better (then that rate would have been the same in the same sort of place 30 years ago, but I wasn't there to check and have no reliable data), or they are less discriminated against nowadays (and the rates should grow in the entire population, I suspect it but again I have not checked).
It's also possible that those portions of the schooling system which discriminate the less against left-handed also happen (surprise !) to give the best education. So you end up with a correlation (without causation...) between the top tier of society, and left-handedness.
In any case, the rant against left-handed sounds like it's paid for by some intelligent design society (you know, the left hand is the one of the devil) Pierre
Either the left handed really perform better
Hmmm... They might perform better in that intellectual environment. There may be a typical French bias at play there, because of the selection of the élite through the engineering school / mathematics pathway. You're clearly a dangerous pinko commie pragmatist.
left-handers did well enough in "expressive English", but were less competent than right-handers in "social/emotional skills, gross and fine motor skills and receptive English skills"
research shows that left-handers are more likely to suffer from language disorders, autism, dyslexia, "schizotypal behaviour patterns", seizures and post-traumatic stress disorder
However, correlation is not transitive. That A is correlated with B and B correlated with C tells you very little about the correlation of A with C. (This is an exercise in spherical trigonometry :-) Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith
However, correlation is not transitive. That A is correlated with B and B correlated with C tells you very little about the correlation of A with C. (This is an exercise in spherical trigonometry :-)
If A,B,C are three series of numbers of the same length arranged in N triplets, I see a geometrical explanation why correlation should be transitive (it is no trigonometric however).
First high correlation implies points are close to a plane around X axis (and not Y,Z axis), second high correlation implies they are close to a plane around Y axis (and not X, Z axis). The intersection of the two plane is a line unless they are one and the same plane. If it is a line, the third correlation is also pretty high. In order to have the two planes intersect at a very narrow angle (to degrade the 3rd correlation), you need very different orders of magnitude between the standard deviations of the first and second series...
ah OK I get it, this is were you have spherical trigonometry to express the angle in terms of the standard deviation. Forget it. Pierre
This all follows from considering that "covariance" is an "inner product". The Cauchy-Schwarz inequality gives you "covariance is less than the product of standard deviations".
Does that answer your question? Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith
