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 0.02 with 99% confidence if (a) she uses a previous estimate of 0.48? L..... (b) she does not use any prior estimates? X Table of critical values E...... Click the icon to view the table of critical values. (a) n= (Round up to the nearest integer.) Level of Confidence, Area in Each Tail, Critical Value, z (1 - a) . 100% 90% 0.05 1.645 95% 0.025 1.96 99% 0.005 2.575