Last year, Lipton Tea Company conducted a mallintercept study at six regional malls around the country and found that 20% of the public preferred tea over coffee as a midafternoon hot drink.

This year, Lipton wants to have a nationwide telephone survey performed with random digit dialing.

What sample size should be used in this year's study to achieve an accuracy level of ±2.5% at the 99% level of confidence? What about at the 95% level of confidence?