Public Health Research MethodsDaniel, J. (2015). Sampling: the foundation of good research. In Guest, G., & Namey, E. Public health research methods (pp. 511-552). 55 City Road, London: SAGE Publications, Inc. doi: 10.4135/9781483398839
Read Chapter 17, Sampling: The foundation of good research. It reviews the steps in determining a sample for quantitative methods.