Manag., July-2018 – Q45
0. Which one among the following relates to the probability-based sampling technique?
- Option : C
- Explanation : Probability sampling refers to the sampling method in which all the members of the population has a pre-specified and an equal chance to be a part of the sample. This technique is based on the randomization principle, wherein the procedure is so designed, which guarantees that each and every individual of the population has an equal selection opportunity. This helps to reduce the possibility of bias.
Statistical inferences can be made by the researchers using this technique, i.e. the result obtained can be generalised from the surveyed sample to the target population. The methods of probability Sampling, are provided below:
> Simple Random Sampling
> Systematic Sampling
> Stratified Sampling
> Cluster Sampling
Types of Sampling
Probability Sampling
> Random Sampling: Each person in the universe has an equal probability of being chosen for the sample and every collection of persons of the same size has an equal probability of becoming the actual sample. Simple Random Sampling = Sampling without replacement
>Systematic Sampling: A sample constructed by selecting every kth element in the sampling frame. Systematic sampling is more practical in that it is less work and thus provides more information per dollar. It also may reduce error. (The more complex the method, the greater opportunity for error.)
Stratified Random Sampling: Is obtained by separating the population elements into overlapping groups, called strata, and then selecting a simple random sample from within each stratum. Example: Rank order: full professor, associate professor, etc. After this is done a random or systematic sample is drawn within each group.
>Cluster Sampling: A simple random sample-in which each sampling unit is a collection or cluster, or elements. For example, an investigator wishing to study students might first sample groups or clusters of students such as classes or dormitories, and then select the final sample of students from among clusters. Also called area sampling. Advantage: saves time and money. Disadvantage: error.
Non-Probability Sampling: when in a sampling method, all the individuals of the universe are not given an equal opportunity of becoming a part of the sample, the method is said to be Non-probability sampling. Under this technique as such, there is no probabilityattached to the unit of the population and the selection relies on the subjective judgement of the researcher. Therefore, the conclusions drawn by the sampler cannot be inferred from the sample to the whole population. The methods of non-probability sampling are listed below:
> Convenience Sampling
>Quota Sampling
>Dimensional Sampling
>Judgement or Purposive Sampling
>Snowball Sampling
