Epäsatunnaisissa

Epäsatunnaisissa refers to a concept in statistical sampling. It describes a sampling method where the selection of sample units is not based on random chance. In contrast to random sampling, where every member of the population has a known, non-zero probability of being selected, in non-random sampling, this probability is either unknown or zero for some or all members.

There are several types of non-random sampling methods. Convenience sampling involves selecting individuals who are most easily accessible to the researcher. Quota sampling aims to fill predetermined quotas for different subgroups within the population, but the selection within these subgroups is not random. Purposive sampling involves the researcher's judgment to select individuals who are deemed to be representative of the population or possess specific characteristics. Snowball sampling is used when the population is difficult to identify and recruit, where existing study subjects recruit future subjects from among their acquaintances.

While non-random sampling can be more convenient and less expensive than random sampling, it carries a significant risk of bias. The lack of randomness can lead to a sample that is not representative of the target population, potentially affecting the generalizability of the study findings. Therefore, researchers must carefully consider the implications of using non-random sampling and acknowledge its limitations when interpreting results. It is often employed in exploratory research or when random sampling is not feasible.