An analyst believes that the iPad mini will end up causing a reduction in sales of the regular, full-size iPad of up to 1 million units in the fourth quarter as customers opt for a cheaper and smaller model. The idea is that one out of every five iPad mini sales will be a sale that would have gone to the 9.7-inch older brother.

Cannibalizing your own company's sales is never a good idea, however, it is predicted that Apple's overall tablet sales will continue to grow, despite 20 percent of sales being cannibalized. Gene Munster, an analyst for Piper Jaffray, expects the iPad mini to boost Apple's sales from 21 million to 25 million for the fourth quarter.

He further estimates that Apple will sell 95 million tablets in 2013, thanks to the iPad mini. This is up from his previously predicted 86.5 million tablets. Munster expects 25 percent of those sales to be the iPad mini, which he thinks will start at $249 to $299. It's not clear how this will affect profit, though I'd assume there is less profit on the mini as opposed to the full-size iPad.