Thread: How large should my survey be?

I need to conduct a 10min long marketing survey with 6 to 7 questions . How large should my sample size be to have results representative of a 1000000-large population group, considering I want to achieve a 95% confidence level?


I have read the formulas:


but how can I reconcile the concept of a questionnaire with the standard deviation of the sample population and the error E? Is there even a mean or proportion to talk about? The only unambiguous part is z = 1.96 for 95% confidence.

Originally Posted by chopet

I need to conduct a 10min long marketing survey with 6 to 7 questions . How large should my sample size be to have results representative of a 1000000-large population group, considering I want to achieve a 95% confidence level?


I have read the formulas:


but how can I reconcile the concept of a questionnaire with the standard deviation of the sample population and the error E? Is there even a mean or proportion to talk about? The only unambiguous part is z = 1.96 for 95% confidence.

Read this: Determining Sample Size