A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.05 with 95% confidence if (a) she uses a previous estimate of 0.28? (b) she does not use any prior estimates? Click the icon to view the table of critical values. (a) n= (Round up to the nearest integer.) (b) n= (Round up to the nearest integer.)