An accounting firm assists small businesses file annual tax forms. It assigns each new client to a CPA at the firm who specializes in companies of that type and size. For instance, one CPA special- izes in boutique clothing retailers with annual sales of about +2 million. To speed the process, each business submits a preliminary tax form to the accounting firm.

(a) Would a normal model be useful to describe the total size of adjustments when a CPA reviews the preliminary tax forms? (For example, suppose the preliminary form claims that the business owes taxes of +40,000. If form completed by the CPA says the tax obligation is +35,000, then the adjustment is - +5,000.)

(b) What data would help you decide if a normal model is appropriate? (You cannot use data from the current year; those data are not yet available.)

(c) If the average adjustment obtained by the CPA who specializes in clothing retailers is - +7,000 (i.e., +7,000 less than indicated on the preliminary form), then what SD implies that all but a few business end up with lower taxes after the work of these accountants? (Assume a normal model for this question.)

(d) Would a normal model be useful to describe the total size of adjustments for all of the CPAs at this accounting firm?