Population size: is the number of people who exist in your audience. How many people exist in the group you want to poll or survey? Maybe you have a mailing list of 4,000 people that you’ll be sending the poll to. Then “4,000” would be your population size. If you have 500,000 visits to your site a month and want to run your poll or survey over a month, then “500,000” would be your population size. If you don’t know your population size, you can “submit the form using industry standards” which are 20,000 sample size, 95% confidence interval, and a 5% margin of error.
Confidence level: tells you how sure you can be of your results. The industry standard that most researchers use is a 95% confidence level.
Margin of error: is the amount (which is usually small) that’s “allowed for” in case of miscalculation or change of circumstances. This means that your responses could be inaccurate (either negatively or positively) by a few points.
Sample size: The larger your sample size is, the more sure you can be that your results accurately reflect the larger population. To get the results you want with the confidence level you want (e.g. 97%) the sample size that’s given to you as a result is the number of responses you’ll need to get the confidence level you want.