Question: The IRS discontinued random audits in 1988. Instead, the IRS conducts audits on returns deemed questionable by its Discriminant Function System (DFS), a complicated and highly secretive computerized analysis system. In an attempt to reduce the proportion of nochange audits (that is, audits that uncover that no additional taxes are due), the IRS only audits returns the DFS scores as highly questionable. The proportion of nochange audits has risen over the years and is currently approximately 0.25 (T. Herman, Unhappy Returns: IRS Moves to Bring Back Random Audits, The Wall Street Journal, June 20, 2002, p. A1). Suppose that you select a random sample of 100 audits. What is the probability that the sample has
a. between 24% and 26% no-change audits?
b. between 20% and 30% no-change audits?
c. more than 30% no-change audits?