Mittetõenäosuslikus

Mittetõenäosuslikus refers to a set of statistical sampling methods where the selection of sampling units is not based on random chance. This contrasts with probability sampling, where every member of the population has a known, non-zero chance of being selected. In non-probability sampling, the researcher's judgment or convenience plays a significant role in selecting the sample.

There are several types of non-probability sampling. Convenience sampling involves selecting participants who are readily available and easy to reach. This method is often the quickest and cheapest but is prone to significant bias as the sample may not be representative of the target population. Quota sampling aims to create a sample that reflects the proportions of certain characteristics within the population, such as age, gender, or socioeconomic status. However, the selection within these quotas is still non-random. Purposive sampling, also known as judgmental or selective sampling, relies on the researcher's expertise to choose individuals who are considered most appropriate for the study's objectives. Snowball sampling is used when the target population is difficult to access. In this method, initial participants are asked to refer other potential participants, creating a chain.

Non-probability sampling methods are often employed in exploratory research, qualitative studies, or when probability sampling is not feasible due to logistical or financial constraints. While they can provide valuable insights and generate hypotheses, the findings from non-probability samples cannot be generalized to the larger population with the same level of confidence as those obtained from probability sampling. The lack of random selection makes it impossible to calculate sampling error or establish statistical significance in the same way. Researchers using non-probability methods must be mindful of potential biases and clearly state the limitations of their study.