Beware of averages. The average person has one breast and one testicle.
Notes from Wikiquote
Former Gov. Dixy Lee Ray, speaking at a Forward Washington conference in Pasco, warned her audience against misuse of statistics. The Tri-City Herald quoted the always quotable Ray as saying: Beware of averages. The average person has one breast and one testicle. — Jean Godden, "How Many Lawyers Do You Need To Fry Spam?", October 9, 1991, Seattle Times. Accessed 29 August 2012.