In statistics the term "population" has a slightly different meaning from the one given to it in ordinary speech. It need not refer only to people or to animate creatures - the population of Zambia, for instance or the dog population of Lusaka. Statisticians also speak of a population of objects, or events, or procedures, or observations, including such things as the quantity of lead in urine, visits to the doctor, or surgical operations. A population is thus an aggregate of creatures, things, cases and so on. Although a statistician should clearly define the population he or she is dealing with, they may not be able to enumerate it exactly. A population is the entire group that you want to draw conclusions about. A sample is the specific group that you will collect data from. The size of the sample is always less than the total size of the population. In research, a population doesn't always refer to people. It can mean a group containing elements of anything you want to study, such as objects, events, organizations, countries, species, organisms, etc. A. What is sampling error? List the strategies to be employed to reduce sampling errors? B. Explain the advantages of sampling in research. C. Describe the criterions involved in determining sample size in a research study. D. Enumerate the non-probability sampling techniques.