SAMPLING

Sampling

Sampling

Importance of sampling frame in a sampling plan

Sampling frame is considered as one of the most vital and most important elements of a sampling study because of the fact that all of the results, conclusions and the recommendations depend on the sampling frame of a research work. Sampling frame is basically a comprehensive description of initial set of all the units of observation. Most often, the concept is applied to the unit of observation that particularly includes the quantitative parameter sample.

The sampling frame is a picture of the research conclusions in a concrete case. This can be a mailing list, an index, a customer database may be, the telephone directory or map, from which the sample is selected. For special populations, such as architects, artisans, etc., are often called "list brokers" consulted to access addresses (Casey, 2001).

Effect of poorly specified sampling on the research process

In relation to the above concern, it can be said that the selection effects can occur whenever the sampling frame is not complete. The problem with the sampling based on the aforementioned lists and directories then, is that there may be problems with the representativeness and that if this example is not the latest standards and are therefore not the complete defined population comprise. The phone directory is an example of an incomplete sampling frame. A selection basis can include individuals who are not allowed for the investigation (Casey, 2001). For case in point, start up a business, a study on customer satisfaction for which the database includes people who are not customers and people who are outside the community (Cochran, 2007). To narrow this problem, appropriate screening questions at the beginning of interviews or online surveys are important.

Convenience sampling

The studies that employ convenience sampling are not invalid; the reason of this statement is that a convenience sample contains a group of participants who select themselves into a study. Clinical trials for medical treatments frequently use this type of design. Because, it is impossible to sample patients at random, these studies rely on the willingness of patients to volunteer for a clinical trial. Once in the clinical trial, patients are assigned at random to receive the drug being tested.

Convenience sampling is a non-probability sampling method in which the sample items are selected according to their convenience population is first divided into clusters and a simple random sample of clusters is then selected. Convenience sampling is most often used and indeed the most convenient form of a simple sample. To create a convenient sample, the researcher simply uses volunteers from the people with the basic requirements of the study. Convenience sampling refers to a non-representative sample selection on the basis of simple availability. While in the market and public opinion research, except for qualitative preliminary studies without these, it is common in psychology, working primarily with student test subjects. In addition to this, a convenience sample has the advantage of being easily formed. However, it is impossible to assess the degree of representativeness of the sample population (Krishnaiah ...