A population has standard deviation a 17.5. Part 1 of 2 (a) How large a sample must be drawn so that a 99.8% confidence interval for u will have a margin of error equal to 4.5? Round the critical value to no less than three decimal places. Round the sample size up to the nearest integer. A sample size of is needed to be drawn in order to obtain a 99.8% confidence interval with a margin of error equal to 4.5. Part 2 of 2 (b) If the required confidence level were 90%, would the necessary sample size be larger or smaller? Smaller , because the confidence level is lower