Stratified sampling method is also called type sampling method. It is a method of randomly selecting samples (individuals) of different layers from the whole that can be divided into different subgroups (or layers) according to the specified proportion. The advantage of this method is that the sample is representative and the sampling error is small. The disadvantage is that the sampling procedure is simpler and more complicated than random sampling. Stratified sampling in quantitative survey is an excellent probability sampling method, which is often used in survey.