(1) Different sample selection:
The key investigation is to select some key units as samples, and the total number of symbols of key units accounts for the vast majority of the total number of symbols of all units. ?
The typical units in the typical investigation are consciously selected on the basis of analyzing the overall situation. ?
(2) What are the different purposes of the survey?
The purpose of key investigation is to grasp the basic situation of the whole phenomenon; ?
The purpose of a typical investigation is to make an in-depth and meticulous investigation and study new situations and problems in the overall phenomenon. ?
(3) Suitable for different venues?
The key survey is applicable to the occasions where some units can focus on reflecting research projects or indicators;
The typical investigation is more flexible, that is, it can focus on qualitative research and lateral weight research, that is, it can study several typical and some typical; ?
(4) Is the reliability of the inferred population different?
The key investigation cannot infer the total amount; ?
In a typical investigation, the total amount can be inferred under certain conditions, but the reliability is unknown.