# sampling methods in quantitative research

This involves collecting and gathering information from a small group out of a population or universe. Despite the sample population being selected in advance, systematic sampling is still thought of as being random if the periodic interval is determined beforehand and the starting point is random. Establish theories and address research gaps by sytematic synthesis of past scholarly works. Herein, approached unit suggest researcher the other units which could be included in the study. This Non-probability method is often used during preliminary research efforts to get a gross estimate of the results, without incurring the cost or time required to select a random sample. The concept of randomness has been basic to scientific observation and research. Each member of the population has an equal and known chance of being selected. A systematic random sample is obtained by selecting one unit on a random basis and choosing additional elementary units at evenly spaced intervals until the desired number of units is obtained. Since simply random sampling a population can be inefficient and time-consuming, statisticians turn to other methods, such as systematic sampling. This is the reason why most researchers rely on sampling techniques like convenience sampling, the most common of all sampling techniques. In a study wherein the researcher likes to compare the academic performance of the different high school class levels, its relationship with gender and socioeconomic status, the researcher first identifies the subgroups. There is very little effort in the part of the researcher when performing this sampling technique. Expensive and time-consuming. This process of listing is called the sampling frame. Stratified random sampling is used when the researcher wants to highlight a specific subgroup within the population. Having overlapping subgroups will grant some individuals higher chances of being selected as subject. 20 of them are selected in random. This sampling technique gives the researcher limitless chances of fine tuning his research methods and gaining a vital insight into the study that he is currently pursuing. Convenience sampling is used in exploratory research where the researcher is interested in getting an inexpensive approximation of the truth. After the required sample size has been calculated, every Nth record is selected from a list of population members. You can number each of the small plots up to 9 and then you can use series of numbers like 8 6 3 1 6 2 9 3 5 6 7 5 5 3 1 and so on. These procedures are very clearly defined, making it easy to follow them. The goals and techniques associated with probability samples differ from those of nonprobability samples. The process involves nothing but purposely handpicking individuals from the population based on the authority’s or the researcher’s knowledge and judgment. In non-probability sampling, the degree to which the sample differs from the population remains unknown. Within systematic sampling, as with other sampling methods, a target population must be selected prior to selecting participants. Sequential sampling is a non-probability sampling technique wherein the researcher picks a single or a group of subjects in a given time interval, conducts his study, analyzes the results then picks another group of subjects if needed and so on. Cluster sampling is a method used to enable random sampling to occur while limiting the time and costs that would otherwise be required to sample from either a very large population or one that is geographically diverse. Equating experimental and control groups in an experiment. The judgemental sampling is used in cases where the specialty of an authority can select a more representative sample that can bring more accurate results than by using other probability sampling techniques. Unfortunately, there is usually no way to evaluate the reliability of the expert or the authority. All units of the population do not an Snowball sampling relies on referrals from initial subjects to generate additional subjects. The important thing to remember in this technique is to use the same sampling fraction for each stratum regardless of the differences in population size of the strata. the sample from the entire population. If a study aims to investigate a trait or a characteristic of a certain subgroup, this type of sampling is the ideal technique. Selecting a group of individuals for observation who are representative of the population about which the researcher wishes to generalize, or. Then you apply dose A to 1, B to 2 because dose B is already used on plot 6 and so on. Dividing the employees into clusters based on geographical location and then selecting the clusters randomly. There exists a chance in simple random sampling that allows a, The main advantage of using systematic sampling over, The process of selection can interact with a hidden periodic trait within the population. Other researchers use a modified systematic random sampling technique wherein they first identify the needed sample size. Be sure to understand the limitations of the technique. In randomized controlled trials, the research participants are assigned by chance, rather than by choice, to either the experimental group or the control group. Once a fixed starting point has been identified, a constant interval is selected to facilitate participant selection. This is commonly used in studies that may be looking at issues like the homeless households. This sampling technique is also useful in documenting that a particular quality of a substance or phenomenon occurs within a given sample. In this type of population sampling, members of the population do not have equal chance of being selected. This technique is easy, fast and usually the least expensive and troublesome convenience sample results when the more convenient elementary units are chosen from a population for observation.