Answer:
d. sampling unit
Explanation:
<u>Sampling unit:</u>
Refers to the unit or group of elements that are selected from an original population during an investigation. The sampling unit might be composed of a statistical unit or a group of statistical units.
The statistical unit or element is the elemental unit that composes the target population.
The sampling unit is a basic concept to keep present during the development of the investigation project. It is the minimal unit of observation that will be used to take information about the variables of interest. All the sample unit composes the population and is defined by an <em>N</em>, while only some representative sample units compose the sample, and are represented with an <em>n</em>.
So, the whole population can not be measured because of its size, or the individuals´ characteristics, among other many factors. So we need to take a random and representative sample or group of the population to proceed with our investigation. This sample or group is composed of some of the original population individuals, which are defined as "sample units".
