Sampling -probability sampling involves two types: the
Sampling is a process of obtaining information regarding a subject from a large group for the purpose of research analysis. It is important component of the methodology which seeks to find answers to the research questions. There are different methods of collecting a sample. According to our textbook, there are two types of sampling: probability and non-probability. Probability sampling is a random sample in which each member in the population has an equal chance of being selected, in the contrast, non-probability sampling is a method where some individuals in the population have no chance of being selected. Non -probability sampling involves two types: the convenience sample and the purposive sample. Purposive sample is non-randomly selected. It chooses respondents or participants for particular qualities or characteristics. This sample also not representative of entire population. The convenience sample is one the most common methods. The advantage or disadvantages of this method depends on the type of study being conducted. If the purpose for research to covers small part of population, then convenience sampling is appropriate. However, if the purpose from research to cover whole population, then this method is not very reliable. Pros of convenience sampling: Convenience sampling can be very useful in exploratory studies regarding the topics which allow to gather primary data and help making decision for further measures. This method of data collection is easy to access as it obtained by using any group who willing to participate and happen to be available for research without requiring extra effort from researcher to gather data. According to Houser (2018) that convenience sampling is ” method of selecting a sample that includes subjects who are available conveniently to the researcher” ( p 169). Application of convenience sampling is the cheapest to implement and easiest to collect in short duration of time compared to other sampling methods. Cons of convenience sampling: Data being gathered with this technique represent views of a particular group but not whole population. There is possibility of sampling error and inaccuracy since this process is biased. Larson (2015) defines sampling error, ” is the difference between the results of a sample and those of the population” (p, 20). Convenience sampling contain unknown quantities of error, which may put threat to the validity of results. As stated by Houser (2018), ” Sampling bias increases sampling error as well as the chance the researcher will draw misleading conclusions” (p, 161). Convenience sampling is not reliable to formulate rules and generalized conclusions just because the data collected based on chosen people who are easily accessible. Snowball sampling is a specific kind of convenience sample: it relies on finding one or a few people who fit the sample criteria and this group help to locate more additional individuals. This method is used often when sampling a unique population and is appropriate when studying interpersonal relationships. In my work, I have seen convenience sampling put in use when our manager plan to buy new equipment or product for our floor, then she has to test them prior to purchase them by day shift nurses. It is not necessary that every nurse on the floor test the subject but only day shift nurses who are convenience samples, try the selected product and fill the survey about it.