Surprisingly, it would appear from Figure 5 (see image below), that contrary to popular myth, Black males have shorter erect lengths than their Caucasian counterparts. [!] The average flaccid length among Blacks however was 93.8mm (3.7") compared to 87.7mm (3.4") for Caucasians, which may be responsible for the impression that Black men have greater erect dimensions.
There was a significant difference in length between Caucasians and both Hispanic and East Asians (those of Chinese, Japanese, Korean or Vietnamese descent). Whereas with Hispanics, such a difference was limited to erect length only, with East Asians all five measurements were statistically lower in comparison to Caucasians. Although part of this difference may be due to the shorter stature of East Asians (see "On Correlations" below), height matched comparisons with Caucasian subjects nevertheless failed to alter this finding.
The figure to the left summarizes the results of question 44, in which men were asked to rate members of their own ethnic group with respect to size. Of particular interest was the response of East Asian subjects. Among East Asians residing in the East, 31% felt that they were generally of modest size, compared to 56% of those living in the West. This is probably due to the fact that Western countries tend to be more racially diverse, allowing for greater interaction and hence comparison with men of different ethnic backgrounds. It is also interesting to note that the vast majority of Black subjects stated that they tended to be well endowed; an opinion which was not borne out by the results of this study.
http://www.sizesurvey.com/fig5.gif
Source:
http://www.sizesurvey.com/result.html