Description of Statistical Sidebar: Convenience Sampling, Random Sampling, and Snowball Sampling: How Does Sampling Affect the Validity of Research?
Sampling is defined by Merriam-Webster's dictionary as “the act, process, or technique of selecting a representative part of a population for the purpose of determining parameters or characteristics of the whole population” (n.d.). When conducting research with people (adults or children) who are visually impaired, a low-incidence disability, sampling is a major issue. Inferential statistics are based on probabilities that are more accurately predictive with higher sample sizes. The more participants in a study, the more protected the results of the study are from the influences of random error for which a researcher cannot control. When researchers use the expression “controlling for random error” in their articles, they are talking about limiting the impact that factors unrelated to the study have on what they are seeking to measure through their research.