The proportion of public accountants who have changed companies in the last 3 years is to be estimated in 5 percent. The 95 percent level of confidence is to be employed. A study conducted several years ago revealed that the percent of public accountants changing companies within three years was 22. (Round up your answers to the next whole number.)
(a) To update this study, the files of how many public accountants should be studied?
(b) How many public accountants should be contacted if no previous estimates of the population proportion are available?