(BQ) Part 2 book "Marketing research" has contents: Basic sampling issues, sample size determination, data processing and fundamental data analysis; statistical testing of differences and relationships, multivariate data analysis, communicating the research results,.and other contents. | 09/11/2014 Page 308 © StockLib/iStockphoto 13 C H A P T E R Basic Sampling Issues LE AR N I N G O B J ECTI V ES 1. Understand the concept of sampling. 2. Learn the steps in developing a sampling plan. 3. Understand the concepts of sampling error and nonsampling error. 4. Understand the differences between probability samples and nonprobability samples. 5. Understand sampling implications of surveying over the Internet. Concept of Sampling sampling Process of obtaining information from a subset of a larger group. Sampling, as the term is used in marketing research, is the process of obtaining information from a subset (a sample) of a larger group (the universe or population). We then take the results from the sample and project them to the larger group. The motivation for sampling is to be able to make these estimates more quickly and at a much lower cost than would be possible by any other means. It has been shown time and again that sampling a small percentage of a population can produce very accurate estimates about the population. An example that you are probably familiar with is polling in connection with political elections. Most major polls for national elections use samples of 1,000 to 1,500 people to make predictions regarding the voting behavior of tens of millions of people and their predictions have proven to be remarkably accurate. The key to making accurate predictions about the characteristics or behavior of a large population on the basis of a relatively small sample lies in the way in which individuals are selected for the sample. It is critical that they be selected in a scientific manner, which ensures that the sample is representative—that it is a true miniature of the population. All of the major types of people who make up the population of interest should be represented in the sample in the same proportions in which they are found in the larger population. This same requirement remains as we move into the .
