Sample frame, sample frame error, and sample error are basic concepts in sampling. Briefly define and describe each of these concepts. Define probability and nonprobability sampling. What are the advantages and disadvantages of each? Describe the four probability sampling methods in which there is a known chance of a member of the population being selected into the sample. The statement "a sample size decision is usually a compromise between what is theoretically perfect and what is practically feasible" underscores the importance of why a marketing researcher should have a basic understanding of sample size determinations. List and describe the two primary reasons why a marketing researcher should have this basic understanding. Define the terms variability, confidence interval, and acceptable margin of sample error.