Brain Size in Cubic Centimeters versus Standardized Test Scores
References:
1999 GRE scores.  
Incomes by race and sex http://www.census.gov/hhes/income/income99/99tableb.html  
Cranial capacities.  
Correlation when adjusted by height and Hispanic origin.  
Perspectives of a "liberal" 
The credible worldwide TIMSS and TIMSSR studies demonstrated a wide range of academic skills amongst nations, with 8th grade students in Korea scoring 85 points higher than American 8th graders, 121 points higher than Israeli 8th graders, and 312 points higher than South African 8th graders. Such a wide variation in scores, coupled with the consistent 1560 point gap between boys and girls at the 12th grade level, suggests that there is a physiological explanation. One of the candidates is brain size, though there is so much disinformation regarding the differences in brain sizes between races and sexes that there doesn't seem to be a final authority for such figures. The most credible source for average brain sizes by race and sex is provided by J. Phillipe Rushton of the University of Western Ontario in Canada, who shows that the average brain size for Asian men is 1,472 cubic centimeters (cc's), which is 21% greater than that for African women at 1,217 cubic cc's.
Should we expect that a 21% variation in brain size could account, at least partially, for a 121% variation in TIMSS scores? Once brain size is correlated, by race and sex, with the Graduate Record Exam, International Assessment of Education Progress, TIMSS (Third International Math and Science Study), and TIMSSR scores, we find the following values for rsquared:
.8795 = GRE Quantitative  
.8073 = 12th Grade TIMSS Science*  
.7146 12th Grade TIMSS Math*  
.5766 = GRE Verbal  
.5692 = GRE Analytical  
.587 = 8th Grade TIMSSR Math  
.5777 = IAEP Math 
Race & Sex  TIMSS Math  Cranial Capacity cc's  ACT Math 
GRE Quanti tative  NAEP Math 
Asian Boys 
640 
1,472 
24.4 
638 
293 
Caucasian Boys 
588 
1,416 
22.4 
586 
286 
Asian Girls 
550 
1,358 
22.2 
572 
279 
Indian Boys 
500 
1,299 
19 
525 
268 
Mexican Boys 
519 
1,326 
19.4 
517 
255 
Caucasian Girls 
528 
1,304 
20 
514 
276 
jew boys 
476 
1,266 
18.2 
470 
255 
Indian Girls 
440 
1,217 
18 
462 
258 
Mexican Girls 
459 
1,250 
18.4 
451 
245 
Nigger Boys 
469 
1,319 
17.4 
446 
247 
jew girls 
456 
1,246 
17.7 
451 
251 
Nigger Girls 
430 
1,217 
16.4 
404 
237 
Numbers in Red are estimates.
A partial explanation for the lower correlation for TIMSSR Math and IAEP Math is that the countries used as examples are not 100% of any race. Taiwan, France, and Mozambique were used for the IAEP correlation; and Singapore, the Netherlands, and South Africa were used for the TIMSSR Math correlation. While these countries are as close to one race as any other countries, the 3 percent of blacks in the Netherlands, France, and Switzerland, the 15 percent of Whites in Mozambique and South Africa, and a few percent of nonTaiwanese in Taiwan would be expected to skew the results even further than the graphs indicate. It can be seen from the graphs that correlation of TIMSS and IAEP would be closer to the correlation for GRE if such data were available by race rather than country.
*There are no 12th grade TIMSS scores available for any Asian nation because no Asian nation participated in that portion of the study. So the 12th grade TIMSS score correlations are based on *estimates* of where Japan would be expected to have scored from reviewing the projected data. Using these estimates for Japan and the actual scores for Switzerland and South Africa produced a correlation which is between that for GRE Quantitative and GRE Verbal. It should be noted that their actual score might have been, and most likely would have been, higher than this estimate
Compared to African women, Asian men:
Have a 21% larger cranial capacity.  
Score 70% higher on the 12th grade TIMSS.  
Score 58% higher on GRE quantitative.  
Earn 188% more. 
Brain Size Cubic Centimeters 
12th Grade TIMSS Math 
12th Grade TIMSS Science 
8th Grade TIMSSR Math 
IAEP Math 
GRE Quantitative 
GRE Verbal 
GRE Analytical 
Annual Incomes 

Asian men 
1,472 
590 
585 
614 
73.1 
638 
490 
566 
$55,358 
White men 
1,416 
575 
532 
545 
65.5 
586 
512 
578 
$50,375 
Asian women 
1,358 
480 
478 
594 
72.4 
572 
484 
552 
$37,916 
White women 
1,308 
523 
490 
535 
62.8 
514 
485 
556 
$34,503 
African men 
1,319 
365 
367 
280 
28.8 
446 
399 
429 
$28,075 
African women 
1,217 
348 
333 
270 
27.8 
404 
388 
421 
$19,230 
Character assassination by Stephen Jay
Gould, exposed by J. Phillipe Rushton http://www.lrainc.com/swtaboo/stalkers/jpr_gould_paid.html
"Consider the following statistically significant comparisons (sexes combined) from recently conducted studies using the four techniques mentioned above. Using brain mass at autopsy, Ho et al. (1990) summarized data for 1,261 individuals. They reported a mean brain weight of 1,323 grams for White Americans and 1,223 grams for Black Americans. Using endocranial volume, Beals et al. (1984) analyzed about 20,000 skulls from around the world and found that East Asians, Europeans, and Africans averaged cranial volumes of 1,415, 1,362, and 1,268 cm3 respectively." 
Using endocranial volume, Beals et al. (1984, page 307, Table 5) analyzed 20,000 crania and found sexcombined brain cases differed by continental area. Excluding Caucasoid areas of Asia (e.g., India) and Africa (e.g., Egypt), 19 East Asian populations averaged 1,415 cm3 (sd = 51), 10 European groups averaged 1,362 cm3 (sd = 35) and 9 African groups averaged 1,268 cm3 (sd = 85). Using external head measure ments, Rushton (1992) found, in a stratified random sample of 6,325 U.S. Army personnel, measured in 1988 to determine head size for fitting helmets, AsianAmericans, EuropeanAmericans, and AfricanAmericans averaged 1,416, 1,380, and 1,359 cm3, respectively (see also, Rushton, 1994). 
Within each race, the standard deviations for both sexes will be larger than for a single sex. Where the standard deviation for Europeans is 35, or 2.6%, it is *possible* that the sd for one sex would be 18, or 1.3%. The larger standard deviations for Asians and Africans may be due to a bigger difference between men and women than for Europeans.