How large a sample should be selected to provide a 95% confidence interval with a margin of error of 10? Assume that the population standard deviation is 50. (Round your answer up to the nearest whole number.) In a survey, the planning value for the population proportion is p* = 0.28. How large a sample should be taken to provide a 95% confidence interval with a margin of error of 0.05? (Round your answer up to nearest whole number.)