Pennsylvania lottery. In 1980, millions of viewers watched as the number 666 was drawn for the Pick 3 Pennsylvania lottery. Although as likely as any other number, lottery authorities and local bookmakers became suspicious when they noticed that a large number of tickets were purchased for the eight numbers 444, 446, 464, 466, 644, 646, 664, and 666.

Soon, a handful of players came forward to claim approximately $1.8 million of the then-record

$3.5 million payout. Officials eventually discovered that 8 of the 10 balls were weighted, giving them almost no chance to be selected in the drawing. Is this an example of special- or common-cause variation? Explain.