Examples of Sample Sizes in Research

There are several factors to consider when choosing the sample size for your study. You must also understand statistics to select an appropriate sample size for your research. This article aims to bring everything together so you can make an informed decision. The formula is beneficial for continuous data. Categorical data, however, are not suitable for using the sample size formula.  Here is a sample size example in research!

Justifications for sample size

Sample size justifications must be clear and persuasive, and the reader should be able to determine the validity of an author’s decisions. This paper investigates sample size justifications in four research articles. The articles describe the authors’ confidence in their sample size justifications. For example, SHI139 cited low response rates as a rationale for choosing larger sample size. On the other hand, BJHP04 argued that smaller sample size was unnecessary because the low response rate was so low.

Justifications for sample size are essential for any research study. Researchers must consider whether the effect sizes they are analyzing are plausible and exciting and if the sample size chosen is insufficient to detect them. They must also determine the confidence intervals around effect sizes and the minimal statistical significance. This means considering how plausible an effect size may be in the research area being examined. By incorporating these factors, researchers can make an informed decision about sample size.

Formulas for calculating sample size

There are several formulas for calculating sample size in research, and they all depend on several variables. The study’s primary outcome is the one being tested and the level of statistical significance desired. For example, in a study of a new screening test for Down Syndrome, it is essential to determine how many children in a sample will detect the disease. Typically, the sample size for such a study is 50 children. However, this number can be as low as 20.

In other words, a study conducted two years ago found that 27% of first-year students were smokers. Now, the investigator can use this estimate when planning the following research. This sample size will give them a 95% confidence interval, which means they will have an equal chance of finding the true prevalence of smoking. Further, this will help them calculate the sample size for the following study with the same level of precision and confidence.

Justifications given by the authors

The justifications authors give for using a specific sample size in a scientific study have been studied by qualitative content analysis. We found eleven reasons for the sample size, illustrated with excerpts from relevant articles. Table 3 indicates the frequency of these justifications. It is essential to remember that sample size is not always an indicator of research quality. The authors must be honest about the limitations of their research.

When using small sample size, data saturation is one of the primary justifications given by authors. Most studies invoked this principle, and a small sample size does not have as many problems as some belief. One study explicitly referred to data saturation, while another did not use the term. BMJ13 included data beyond the point of saturation to assess the consistency of findings. The current study has several limitations, but the sample size was sufficient to identify no new themes.

Commonly invoked the principle of data saturation

While there are ways to circumvent the commonly invoked principle of data saturation, researchers should keep in mind that it has its limitations. The principle is generally most useful when applied in a specific approach, such as qualitative research. To avoid pitfalls, researchers should ensure that the standard is embedded in the research process. 

While many qualitative researchers face this problem, the fact remains that failure to reach data saturation can have detrimental effects on the quality of the resulting content. Although saturation is not universally applicable, it should be a goal for every researcher. In qualitative research, specific data collection methods are more likely to reach saturation than others. Furthermore, the principle is highly dependent on the design of the study. Regardless of the technique, researchers should remember that saturation is a crucial issue to consider before undertaking any research.

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