“In God we trust. All others must bring data.” — W. Edwards Deming.
A sample is a subset of the universe that is used for making conclusions or inferences about the universe. It reduces the time, effort and cost in estimating parameters of interest to marketers such as brand awareness, penetration, brand equity, market share, sales or distribution.
This chapter reviews the different sampling methods, and the mathematics of computing sample sizes for retail tracking and quantitative research studies. It covers the sampling standards commonly used by research firms. It also explains sampling and non-sample errors, and their impact on data accuracy.