Is it appropriate to quantify the expected response rates by ethnic group using a simple random sample as the test's sampling plan?

Answer 1

It would depend on the question(s) you are asking.

Answer 2

designing a direct marketing campaign for an online clothing retailer. As part of your design, you quantify the expected response rates by ethnic group. Your definition of the term "ethnicity" follows that of the U.S. Census Bureau (e.g., Hispanic, Asian, African American, etc.). You want to test your campaign using 1,000 randomly selected households, but you want your sample to mimic the US population in terms of the proportion of different ethnicities (e.g., if Hispanics constitute about 12 percent of the US population, 12 percent of your sample should be Hispanic).