Introduction
Sampling is extremely important for conducting research in education, as it can have a significant effect on the research outcome. A sample is a collection of elements meant to represent a population under analysis. While the best research strategy is to conduct a census, which is a study of the entire population of interest, there is usually a lack of time and resources to do so (Check & Schutt, 2012). Thus, it is critical for researchers to understand how to take a valid sample in educational settings.
Main body
The first step to taking a sample is to define the population under analysis. According to Check and Schutt (2012), a population is an entire set of entities to which findings are expected to be generalized. Population can be as broad as teachers in the US, or as narrow as teachers of Polk County Elementary School math teachers. In the second case, however, sampling will not be needed, as the population is small enough to conduct a census.
After selecting a population, it is crucial to assess its diversity. Elements have various characteristics, and it is crucial to understand these characteristics to ensure unbiased results (Check & Schutt, 2012). For instance, if researchers want to study elementary school teachers, they need to understand that there are different types of schools, such as public schools, private schools, boarding schools, and Christian schools. Students may also have a variety of characteristics, such as income level, ethnicity, cultural background, and health status. Researchers need to realize all these characteristics to make sure that all types of students are represented in the sample. At the same time, understanding the population can help to assess the generalizability of the findings.
After acquiring a full understanding of the population, it is critical to select an appropriate sampling method. Sampling methods are divided into probability sampling methods and non-probability sampling methods (Check & Schutt, 2012). In probability sampling methods, the likelihood of participation of different types of elements depends on chance (Check & Schutt, 2012). While this method is used very often due to a decreased possibility of sampling bias, there are two problems that should be considered. First, if a sampling frame is incomplete, the sample of the population will not be random. Second, non-respondents differ considerably from respondents, which can be a source of bias.
Conclusion
The final step of taking an adequate sample is selecting a sample size, which appears to be the most intricate endeavor. When researchers select a sample size, they need to understand what sampling error they agree to. The less sampling error is expected, the larger the sample size should be (Check & Schutt, 2012). The sample size is also affected by the homogeneity of the population, and the analysis performed (Check & Schutt, 2012). Finally, if the researchers need to find weak correlations, they will need a large sample (Check & Schutt, 2012). In order to convert these rules to specific suggestions about the sample size, statistical power analysis can be performed. In summary, researchers can take a valid sample only after answering all the questions listed above.
Reference
Check, J., & Schutt, R. (2012) Research methods in education. SAGE Publications, Inc.