> 3233 young and old adolescents representative of the population
> For the young adolescents, the observed difference in Mechanical Reasoning is equivalent to 10 IQ points, and this difference increases to 13 IQ points for the old adolescents.
> Beyond the observed small average sex difference in the general factor of intelligence (g), the boys' large advantage in mechanical reasoning (MR) must be strongly underscored. This sex difference is not explained by g, and therefore the probable contributions of what is measured by relevant subtests such as abstract reasoning (AR) or spatial relations (SR) can be excluded. The MR difference is still present with almost the same magnitude when the general factor of intelligence (g) is removed. It is also noteworthy that, for the old adolescents, more than half of the variance associated with numerical reasoning (NR) cannot be attributed to g. Thus, we suggest that mental processes captured by these psychological measures are behind the documented male advantage in STEM disciplines
http://atavisionary.com/study-index/intelligence-psychometri...
An observed standard deviation of sex difference in measures of mechanical reasoning at the average of the distribution.
Also, you're ignoring cultural factors. See this article: http://knowledge.wharton.upenn.edu/article/stubborn-obstacle... There are and have been many societies in which women were much better represented in technical fields than they are today in the US. How do you explain that if it's all supposedly just innate biological differences? In the USSR a majority of engineers were women, and the reason for it was actually very logical: Men are stronger and are more suitable for physical labor, and women are thus more suitable for knowledge jobs.
And there are many character traits that men have on average more than women that make them worse engineers. A higher prevalence of mental illness, for starters. More of a tendency to be overly verbally combative and thus detrimental to team functioning. Less ability to focus on "boring" tasks and study, which is why you now see girls dominating boys in school performance at all levels, kindergarten through university.
Who is more "suited" to be an engineer is an entirely different discussion that is not even close to being resolved. What I was talking about was the very real fact that most women in tech experience gender-related discrimination that makes them feel unwelcome. That assuredly has a real effect and is on less shaky grounds than arguing from biological factors.
But I don't want to get drawn into this discussion because I really do have lots of work to get done today. Just refer to everything that was said in the wake of Damore -- I'm sure we wouldn't cover any new ground that wasn't already covered then.