When doing a research It is impossible to do some extensive analysis on all the subjects if there are more than hundreds of objects. It is best to take few subject or object that represent all of them. Few object of the research were named as Sample. Sample is part of population that will be investigated and the sample must have at least one similar characteristic either natural or unnatural. Natural mean it have common similarities by nature while unnatural means it have similarities because they way the researcher think about it. A chosen sample of the research will be generated toward entire population. Representative sample will influence the validity of the result.
There are six kinds of sample known. All of them will be explained below. They are:
1. Random Sampling
It is the way to take the sample where each of research unity from population has the same chance to choose the sample. Random sampling mean the sample were chosen randomly by the researcher. It is used if there are lots of objects that need to be researched. It have some advantages such as able to get more reliable information as the subjects or objects were not chosen manually. The result will differ as the samples are random.
2. Systematic Sampling
It is taking sample only take the first element while another is chosen by the certain form. Systematic Sampling is best to be used after researcher added the objects into several categories. usually, the first category was chosen but it is depend on the researcher to select any categories.
3. Stratified Random Sampling
It is taking sample where the population is taken by divided into separate strata or stage with the same chance. Stratified Random Sampling mean the researcher make several categories based on some formula or calculations and those categories have the same chance to be selected by the researcher. The formula or calculations take the most important part at this point.
4. Cluster Sampling
It is taking by groups of individual in the population. If there are lots of groups, selecting Cluster Sampling is a good idea as it grouping population as clusters.
5. Sequential Sampling
It is use the way to take the sample from the little sample then it is analyzed. If the researcher feels uncertain the sample will be developed to big. The subject at this point will be analyzed to get the most wanted sample. If the researcher think the selected sample were not qualified, it will be sent back to the other sample and may getting bigger. This sample is good after several sample was collected to get the most beneficial sample to use in researches.
6. Purposive Sampling
It is taking sample by attention the certain characteristic of population. It is possible to take sample based on some purpose. This point is only useful when the research is targeting the characteristic population. Not recommended for many objects or subjects. If using this method to get the sample, the Researcher should know the characteristic of each sample.
All of six kinds of samples above can be used while creating various documents such as skripsi or thesis. Any students and teachers can use available sample above. Choosing the right method to get the sample is the key for successful research. It is better to learn about the Sample first before doing a research as it is essential for anyone who doing any useful researches. The sampling methods written in this post can be used to get the best sample. Doing research can be fun and improve the skills. Happy doing a research everyone. NISYA (Linatul Ainisiyah).