** Question #1:** Do these statistics fit "your world"? That is, gather data from your people you know, etc.
** Question #2:** Do these statistics fit "the world"? That is, gather data from the Internet, local blood banks, etc.

** Question #3:** Do these statistics fit "each" different nationality? If not, how does this affect the proposed statistics?

** Question #4:** Do these statistics change over time, as note that the statistics provided are from 1981?

Source: *K. Hledik's "How Rare Are You?" **Oregon Mathematics Teacher*, Feb. 1981, p. 28.