Determining Sample Size. Use the given data to find the minimum sample size required to estimate a population proportion or percentage. Robberies Find the sample size needed to estimate the percentage of robberies in Texas that result in arrests. Use a 0.04 margin of error, use a confidence level of 80%, and assume that point estimate is unknown. 206 O 260 O 265 You can now record yourself and your screen at the same time O 256