Page 1 : NONPROBABILITY SAMPLING 225, , ‘ cher choses subjects ;, « Finally, the resear \ 8 subjects from various subgroups when taking i, the proportions noted in the previous step. Broup g into account, , » The sample is representative of the entire population and is ensured by the final step. It al, rmits the researcher to study characteristics and traits that are significant for each sits 2 a, e The main reason of chaosing quota samples is that they permit the researc hers to cad, a subgrou that is of very large interest to the study. This type of sampling is ita, technique to investigate a trait or a characteristic of a certain subgroup Additionally., quota sampling also permits the researchers to continue relationships between subgroups., In some of the studies, traits of a certain subgroup have been found to be interacting with, other traits of any other subgroup. In such cases, it is also essential for the researcher to, utilize this type of sampling technique. a, , Merits, , ° Economical cheap, as there is no need to approach all the candidates., , ¢ Suitable for studies where the fieldwork has to be carried out, like studies related to, market and public opinion polls., , Demerits, , « Although this kind of sampling technique is seen to be wholly representative of the popu, lation, still in some cases it is not so. Keeping in mind that only the chosen traits, population were taken into consideration while forming the subgroups., , e Other traits in the sample may be over-represented in the process of samplin, subgroups. The final sample may have skewed representation of race, age, educatio, attainment, marital status, and a lot more in a study that considers gender, socio-ecome, status, and religion as the basis of the subgroups., , * Not possible to.estimate.errors., * Bias is possible, as investigator / interviewer can select persons known to him., , Snowball Sampling, , So aie noe cena technique that is used by researchers to idertify potential subjects in studies where subjects are har to locate, such as commercial sex, workers, drug abusers, etc. For example, a researcher wants to conduct a study on the prevalence of HIV/AIDS among commercial sex workers. In this situation, snowball sampling is, the best choice for such studies to select a sample., , Therefore, researchers use this sampling method if the sample for studies that are very rare, or are limited to very small subgroups of the population. This type of sampling technique, , works like chain referral. Therefore, it is also known as chain referral sampling. The researcher, asks for assistance from the subject to identify people with a similar trait of interest after, observing the initial subject., , __ Asking subjects to nominate another person with the same, , snowball sampling. Until obtaining sufficient number of subjects,, ise, , es the nominated subjects and continues in the same way. ae, r example, the researcher may choose to use snowball sampling while obtaining sub, a study to observe a rare disease. It is also practical that the patients with similar, , &, , , , , , , , trait is similar to the process of, the researcher then ob