Sample size calculator . If the sample is skewed highly one way or the other,the population probably is, too. Lower margin of error requires a larger sample size. What confidence level do you need?

With a confidence level of 95%, you would expect that for one of the questions (1 in 20), the percentage of people who answer yes would be more than the margin If you create a sample of this many people and get responses from everyone, you're more likely to get a correct answer than you would from a large sample where only See below under More information if this is confusing. The sample size doesn't change much for populations larger than 20,000.

If you don't know, use 20000 How many people are there to choose your random sample from? Conduct your survey online with Vovici. Try changing your sample size and watch what happens to the alternate scenarios. That tells you what happens if you don't use the recommended sample size, and how M.O.E and confidence level (that 95%) are rel

What margin of error can you accept? 5% is a common choice % The margin of error is the amount of error that you can tolerate. Suppose that you have 20 yes-no questions in your survey. Your recommended sample size is 377

This is the minimum recommended size of your survey. Online surveys with Vovici have completion rates of 66%!When you survey a sample of the population, you don't know that you've found the correct answer, but you do know that there's a 95% chance that you're within the margin The remaining 5% of the time, or for 1 in 20 survey questions, you would expect the survey response to more than the margin of error away from the true answer. Alternate scenarios With a sample size of With a confidence level of Your margin of error would be 9.78% 6.89% 5.62% Your sample size would need to be 267 377 643 Leave this as 50% % For each question, what do you expect the results will be?

If 90% of respondents answer yes, while 10% answer no, you may be able to tolerate a larger amount of error than if the respondents are split 50-50 or 45-55. If you don't know, use 50%, which gives the largest sample size. What is the response distribution? Typical choices are 90%, 95%, or 99% % The confidence level is the amount of uncertainty you can tolerate.

What is the population size? The true answer is the percentage you would get if you exhaustively interviewed everyone. Higher confidence level requires a larger sample size. More information If 50% of all the people in a population of 20000 people drink coffee in the morning, and if you were repeat the survey of 377 people ("Did you