Now, in order to become familiar with sampling, you need to become familiar with some terms.
A population, also called a universe, is the entire group of units, items, services, people, etc., under investigation for a fixed period of time and a fixed location.
A frame is a physical list of the units in the population.
The gap is the difference between the units in the population and the units in the frame.
If the units in the gap are distributed like the units in the frame, no problems should occur due to the gap. However, if the units in the gap are not distributed like the units in the frame, a systematic bias could result from the analysis of the frame. For example, if the frame of New York City residents over 18 years ...