Find the sample size needed to estimate the percentage of residents of one region of a country who are left-handed Use a margin of error of one percentage point, and use a confidence level of 90% Complete parts (a) through (c) below a. Assume that p and q are unknown The sample size needed is 6765 (Round up to the nearest whole number as needed ) b. Assume that based on prior studies, about 8% of residents of the region are left-handed The sample size needed is (Round up to the nearest whole number as needed.)