Powerball and other lotteries are often described as a tax on people who are bad at math. In other words, because the state lotteries are used as a source of revenue, on the average you will lose a fixed percentage of money if you buy several tickets. The larger the number of tickets you buy, the more accurately the money you personally lose over time (a figure you can obtain by tracking the cost of tickets and subtracting any winnings and the taxes on those winnings) will track the percentage taken out from the lottery pool to fund state projects.
The actual mechanism which selects Powerball winning numbers is the Halogen machine, manufactured by Smartplay International of Edgewater Park, New Jersey. The numbered balls are mixed in a chamber by a turntable. Randomly selected balls are chosen and sent up through a clear acrylic tube to a display. The machine can be adjusted to draw balls at different intervals and to select different numbers of balls.