What is stratified sampling? The characteristics are: due to classification and stratification, the similarity between various types of units increases, and it is easy to extract representative survey samples. This method is suitable for situations where the overall situation is complex, there are large differences between units and there are many units.
[Edit] Method for determining the number of samples in each layer
Market research methods
A
Desk research
Case study method
B
Non-repeated sampling
C
Random surprise inspection
Reset sampling
draw lots
Product lien test
D
Multidimensional scaling method
Quantitative research methods
Qualitative research methods
Typical investigation method
Telephone survey
Multistage sampling
Equidistant sampling
Independent control quota sampling
Equidistant scale
Equidistant scale
E
Second-hand data survey
Two-way focus group
F
Non-probabilistic sampling
group sampling
Stratified proportional sampling
Hierarchical optimal sampling
G
Observation method
probability sampling
Inflection point investigation
Si Nuo Bao Samplin
H
Conference survey
J
Focus interview method
Empirical judgment method
random sampling
Family diary method
Dealer interview
K
feasibility study
Control experiment method
L
Joint analysis method
Lien investigation
Garbage investigation method
Category scale
M
Interview method
Blind text
Descriptive investigation
Media investigation method
P
Postscript
Judgement sample
Quota sampling
Balance method
Evaluation scale
paired comparison scales
Q
Q classification
rare
random sampling
S
volumetric method
Structural equation modeling
personal interview
Multiple sampling
Experimental research methods
Field research
Digital distribution scale
Random number table method
Order size
T
projection technique
Promotion estimation method
Projection research
exploratory research
W
Literature investigation method
Questionnaire survey method
Network research
Desk research survey
An unprepared visit
online research
X
Query method
Syndicate research
trace analysis
Mutual control quota sampling
Y
Mail survey
Causality investigation
Z
Subjective probability method
Nested sampling method
Major investigation
Door-to-door search method
[edit]
There are three ways to determine the number of samples in each layer:
(1) Stratification ratio. That is to say, the ratio of the number of samples in each layer to the total number of layers is equal. For example, if the sample size n=50 and the population N=500, then n/N=0. 1 is the sample ratio, and the number of samples in each layer is determined according to this ratio.
② Naiman method. That is to say, the number of samples to be sampled in each layer is directly proportional to the product of the total number of the layer and its standard deviation.
③ Non-proportional distribution method. When the number of cases at a certain level is too small in the total, in order to fully reflect the characteristics of this level in the sample, the proportion of the number of samples at this level in the total sample can be artificially and appropriately increased. But doing so will increase the complexity of reasoning.