ItsACaragor t1_jedvhjm wrote on March 31, 2023 at 8:52 AM

30 is not representative at all.

Generally the minimum is 1000 people taken at random to be at least a bit representative

Plain_Bread t1_jeemogj wrote on March 31, 2023 at 1:39 PM

Any sample that is truly taken at random is representative. The question is how narrow of a confidence interval you're looking for. At a sample size of 500, your 95% confidence interval for the proportion of people who answer "yes" to a question can span up to ~10%. If that's good enough for you then there's nothing wrong with that sample size.