Enter the size of the sample drawn from the population being studied.
Enter the proportion of people in the population being surveyed who are expected to answer a certain way on the key measure in the survey. If you are unsure what the proportion might be, use 50% because this produces the maximum possible variation.
Enter the total size of the population you are studying. If the total population you are studying is small or your sample makes up at least 5% of the entire population, entering the population here will reduce the sampling error calculated. If you are unsure what amount to put here, leave it blank.
Select the desired confidence interval to base the sampling error on. A 95% confidence interval is typical.