A letter submitted to the editor of a national newsmagazine was written and signed by a Dr  Shirley Martin who, in the text of the letter, mentions being a professor at a major North American medical school
Knowing that fewer than 5 percent of the professors at such schools are women, the editor reasons that the chances are better than 19 to 1 that the letter was written by a man
Since more than 19 out of every 20 animals in the wildlife preserve are mammals and fewer than 1 out of 20 are birds, there is a greater than 95 percent chance that the animal Emily saw flying between two trees in the wildlife refuge yesterday morning was a mammal.