Ch 5 - Representative Samples

 

     
    In a research study process, it is critical that researchers should take all steps necessary to ensure the reliability of their findings.  The representativeness of the sample used by researches is determinant to make more assertive conclusions about what will be studied and analyzed.  A representative sample is defined by a small quantity of something that accurately reflects the larger quantity, no matter which topic it has been studied. It can be related to several topics as population, students, HIV positive, and etc. 
A representative sample can be used when researches ensure that all relevant types of people are included in a sample and that the right mix of people is interviewed in a survey, for example.

   The whole process of choosing the sample starts with the decision about the sampling method it will be more adequate.  The use of the sampling method is beneficial to ensure the representativeness of the samples. There are two types of sampling: probability sampling and nonprobability sampling.
  
   In probability sampling, the entire population is known, in other words, all individuals in the population have equal chances of being selected. It involves choosing participants or subjects from your target population at random process minimizing potential sample bias,  creating samples that are highly representative of the population.  A sampling method is called biased if it systematically favors some outcomes over others, what could affect the expected results of studies decreasing the accuracy of the results.
The nonprobability sampling uses techniques of non-random processes like researcher judgment or convenience sampling.  Non-probability sampling is most useful for qualitative studies like a survey, for example.  It is more used in studies where it is not possible to draw random probability sampling due to time or cost limitations too. 
It is important to know that has more risks to be biased to be based on common sense. 
The choice about the better technique will be directly related with the accuracy of the research study and it's consistent chances to obtain good results.