Samples are typically used to describe the characteristics of the broader population. Sampling is the process of selecting some entities within a population to draw the general conclusion about the whole population or part of the. In most surveys, sampling is normally used instead of conducting the whole measurements on the entire population. The reason is that sampling is cost-effective in terms of devoted resources and time. Moreover, the information that is drawn from sampling is often accurate.

On the other hand, the study population can be described as the universe or a group of entities upon which the sample can be drawn. The sampling unit in the population is the basic unit concerning the planned sampling procedure. For instance, in determining the diabetes prevalence in a given population using the sampling method, persons would be regarded as the sampling units. Conversely, in surveys that involve households, the sampling unit would be the households.

In this case, the sampling units would be the measurements since they are the basic unit around which the sampling procedure was. Since the population consists of measurements while the sampling procedure is to draw a sample of measurement from this population, then the sampling units in this population would be the measurements. Measurements are in forms of entities that will be taken as the research sampling units.

The sampling unit in any survey or experiment is largely determined by the targeted group of data or information that is available about the population where the samples will be drawn from. Normally, the sampling units are the target groups to be sampled. With regard to the population, the sampling unit will not be that part of the population that is not targeted, but it would rather be the target group. In this case, where the experiment aims at measuring the outcomes or indicators of a single target, which are the measurements, the sample unit will just be the targeted units that are represented by the measurements.