The definition of population is a generalization area consisting of: objects or subjects that have certain qualities and characteristics that are defined by the researchers to be learned and drawn the conclusions.
So, population is not only a person, but also another objects and natural objects. Population is not only the amount of the object or subject studied, but also covering all the subject’s and the object’s characteristics.
For example, conducting research in school X, then this school has a population that could be the number and characteristics of the subject or person. The first definition gives the meaning that the population is a group of people or subjects and objects observed. The second definition gives instruction that people at school X have the characteristics, such as the work motivation, work discipline, leadership, organization climate and others. School also has other characteristics such as policies, work procedures, spatial class, graduates produced and others.
Every person also can be used as population, because every person has various characteristics, such as style of speech, personal discipline, hobby, way of interaction, leadership and others. For example, conducting research on leadership of president Y. then the leadership is the sample of all the characteristics of president Y.
In medical field, one person often acts as the population. Everyone’s blood is the population. To examine it, some blood should be taken as the sample. Data examined from blood samples are applied to the whole blood owned by the people.
The definition of sample is part of the number and characteristics of the population. If the population is large, it is impossible to the researcher to learn everything that is in the population due to limited funds, manpower and time, the researcher can use the sample drawn from the population. What is learned from the sample, the conclusion will be enforced to the population. Because of that, the sample taken from the population must be truly representative.
If the sample is not representative, it is like a blind man that is told to infer the characteristics of an elephant. One person holds the elephant ears; he concludes that it is like a fan. The second person holds the body of an elephant; he concludes that it is like a big wall. One other person holds the tail; he concludes that elephant as small as a piece of string. That's when the sample is not representative; it is like a blind man who makes the wrong conclusions about the elephant.
