The article relates the method used by the staff of Macworld to gauge how easy it is to win in the sales promotion launched by Pepsi and Apple in the U.S. in 2004. The odds of winning the grand prize in the Powerball lottery are one in 80 million. But grab a bottle of Pepsi, Diet Pepsi, or Sierra Mist that's part of the current iTunes Music Store promotion (cosponsored by Apple and Pepsi), and a person has a one-in-three chance of walking away with a free song. The staff put those one-in-three odds to the test and decided to round up as many Pepsis they could find and see if 33.3 percent of them came up winners. They settled on a 30- soda sample size--enough to give meaningful results without depriving too many Northern California Pepsi drinkers of a chance to win free songs from Apple. Since no one can drink 30 sodas in one sitting, the staff found out how many winning caps they had by using a method first posted at MacMerc.com: tilt the bottle to a 25-degree angle, and look at the bottom of the cap. If you see the word again, you're out of luck; if you see the word song or a random string of letters and numbers, you've just won a free song. All told, the 30 bottles of Pepsi products yielded 14 free iTunes songs--a more-than-acceptable 46.7-percent success rate.