There is no hard and fast rule when it comes to the size of the sample used in a study, and there are many aspects to take into consideration. Contrast the factors a qualitative and quantitative researcher must consider when determining the sample size. How does the sample size impact the study? “Quantitative researchers seek to select samples that will allow them to achieve statistical conclusion validity and to generalize their results” (Polit 2012, p. 273). And as our text reminds us there is no simple formula to tell you how large a sample is needed for a study.
The general recommendation our text gives us is “the largest sample size possible. ” The larger sample size that is used increases the validity of the research. So in turn the smaller the sample size for either study increases the sampling error. The researcher should comparing characteristics of the study in relation to the variable, dependent and independent. The size for most studies “depends on the magnitude of the expected effect size, which is usually quantified by a relative risk, odds ratio, absolute risk difference, hazard ratio, or difference between two means or medians.
The smaller the true-effect size, the larger the study needs to be (Hackshaw, 2008, p. 1141). References Hackshaw, A. (2008, November 1, 2008). Small studies: strengths and limitations. European Respiratory Journal, 32(5), 1141-1145. http://dx. doi. org/10. 1183/09031936. 00136408 This discussion will revolve around the topic of control. In quantitative studies, control is an important issue. What does control mean in research? Why is it important? What do you think is meant by controlling intrinsic and extrinsic variables? Give examples of effective ways to control variables in quantitative research.
In qualitative research In research control is a variable in a study that usually remains constant. This variable is what the study results are compared to. This control is what helps the researcher to know if the study was performed correctly or appropriately. When we think about controlling intrinsic and extrinsic variables first we must know what these things are. By definition extrinsic means (Dictionary. com, 2013): being outside a thing; outward or external; operating or coming from without. Intrinsic means: belonging to a thing by its very nature.