Our civic association is planning to implement a survey asking our neighborhood one true false question. I would like to make sure that we obtain an adequate sample size.
Let's assume N = 2500 people, and we want to be 90% confident of our results with margin of error no more than 5%.
We would like to know the minimum sample size. Is there a simple formula to apply? If so can you please share it?
If so, is there an easy way to stratify the sample by some categorical variable such as race. For this example let's assume 25% of the neighborhood is part of a minority group. What is the minimum number of minority households that must be included?