Systematic sampling fixed interval – UGC NET Question

Systematic sampling begins by choosing a random starting point on an ordered list of population elements and then selecting every kth element thereafter, where k is the sampling interval. This procedure is simple to implement and can approximate random sampling if the order of the list is not correlated with the variables of interest. It also ensures a spread of the sample across the entire frame. Therefore, the method described in the stem is correctly called systematic sampling.

Option A:
Option A, systematic sampling, relies on a fixed numeric step to move through the sampling frame, making selection predictable once the start and interval are set but still probabilistic. Its efficiency and simplicity match the description of selecting every kth element.

Option B:
Convenience sampling is a non-probability method where respondents are chosen because they are easy to reach, without using a fixed interval or random starting point. Thus, it is not appropriate here.

Option C:
Cluster sampling selects intact groups or clusters, not individual elements at regular intervals from a list. It is based on groupings rather than on a numeric step, so it does not fit the stem.

Option D:
Purposive sampling is a judgment-based, non-probability method targeting specific information-rich cases and does not involve fixed intervals or an ordered frame. Hence, it is not the correct completion.