Step 3 of 3: Notice this small sample yielded a BIG margin of error. A pollster wants to redo the survey and obtain a smaller margin of error. The pollster still want to create a 95% confidence interval, but would like to create an estimate with an error rate of at most 3%. Find the minimum sample size needed to accomplish this. Remember to round sample size up to the next whole number. You don't necessarily need Excel, you can just use your calculator for this one. (Look back at your section 8.4 notes on how to do this.) n=(z/2)2p(1p)E2 n = ( z / 2 ) 2 p ( 1 p ) E 2 Remember you can estimate p p in the formula using the p p ^ value that you found in step 1