I'm not a statistics expert so I am wondering if someone can give some guidance on need sample size. Here's the scenario:
I have some distinct markets (e.g. LA, NYC, etc...) that we want to be able to compare to an overall national sample. Also would like to be able to compare the markets vs. markets (i.e. LA vs. NYC). If I use one of the sample size calculators I get that I need roughly 400 responses whether an individual city or national. So that would seem to require 400 national plus 400 per market. Problem is that there are over 10 markets making the cost of such a project prohibitive.
Does anyone have a sample size/distribution suggestion for doing such a project?