THE OBJECTIVE OF MOST MARKETING RESEARCH PROJECTS IS TO OBTAIN INFORMATION ABOUT THE CHARACTERISTICS OR PARAMETERS OF A POPULATION. A POPULATION IS THE AGGREGATE OF ALL THE ELEMENTS THAT HAVE SOME COMMON SET OF CHARACTERISTICS, AND THAT COMPRISE THE UNIVERSE FOR THE PURPOSE OF THE MARKETING RESEARCH PROBLEM. INFORMATION ABOUT A POPULATION MAY BE OTAINED BY A SAMPLE, WHICH IS A SUBGROUP OF THE POPULATION SELECTED FOR THE STUDY. SAMPLE CHARACTERISTICS WILL BE USED TO MAKE INFERENCES ABOUT THE POPULATION PARAMETERS. THE INFERENCES THAT LINK SAMPLE CHARACTERISTICS AND POPULATION PARAMETERS ARE ESTIMATION PROCEDURES AND TESTS OF HYPOTHESES.