Example 1: An advertising firm for Belchfire Automotive wants to test a new series of ads. All visitors to Belchfire dealerships are shown the new ads. Of these, 10% buy a new Belchfire 8, compared to .002% of the general population. The new ads must work!

Example 2: A WTVH5 Telephone Poll: "Are you in favor of free chalk for statisticians?" 70% of the respondents are against the proposal, 30% are for it.

Example 3: Testing a fertilizer for corn: Rows 1,2,3 in a field get the fertilizer, while rows 4,5,6 do not. Rows 1,2,3 generate 90 bushels, while rows 4,5,6 generate only 70. So the fertilizer works!

Example 4: A pshchology grad student wants to test whether TV violence causes violent tendencies. She amasses a group of volunteer subjects. To each subject she shows videotapes, either of Buffalo Bills games or Julia Child cooking shows. Then she gives the subject a frustrating task and grades the violence of their reaction on a scale of 10.