Dottie’s Tax Service specializes in tax returns for professional clients, such as physicians, dentists, accountants, and lawyers. A recent audit of the returns she prepared indicated that an error was made on 5% of the returns she prepared last year.

Use the normal approximation to the binomial distribution to answer all parts of this question. Assuming this rate continues into this year and she prepares 60 returns, what is the probability that she makes errors on: (Round z-score computation to 2 decimal places and the final answers to 4 decimal places.)

a. More than six returns? 

b. At least six returns? 

c. Exactly six returns?