A study conducted several years ago reported that 20% of public accountants changed companies within 2 years. The American Institute of CPAs would like to update the study. They would like to estimate the population proportion of public accountants who changed companies within 2 years with a margin of error of 2% and a 97% level of confidence. Your answers must be whole numbers. a. To update this study, the files of how many public accountants should be studied? Sample size b. How many public accountants should be contacted if no previous estimates of the population proportion are available? Sample size