3 100 0 03 1 Margin of error formula n Multiply by 100 Divide 2 100 n 33 333 n 1111 11 Square each side n 2500 A random sample of about 1100 would have a margin of error of about 13 while a random sample of 2500 would have a margin of error of 2 Question 4 0 02 1 n 50 b Suppose the finance director would like to reduce the cost of the survey by using a random sample of 100 What would be the margin of error for this sample size Substitute 100 for n in the margin of error formula margin of error 100 100 or 10 Margin of error formula n 100 100 A random sample of 100 would have a margin of error of 10 0 5 pts If a survey with a random sample of 2500 students is conducted is it possible that only 20 of the students could respond that they text during class