Making mistakes on your tax return can cost you money. You may
miss out on a larger refund than you claimed, wind up owing more
taxes, plus interest and penalties, or invite an Internal Revenue
Service (IRS) audit. The best defense against these results is a
good offense, namely avoiding errors on your return. Suppose that
on the average 1998 individuals in 2,000 are free from the
numerical errors in preparing their income tax return. If 10,000
forms are selected at random and examined, find the probability
that 6, 7, or 8 of the forms will be in error.