1, simple random sampling method: its method is the simplest. There are no differences or restrictions for all respondents to ensure that each respondent has an equal chance to be drawn. Basic operation steps: all respondents line up and number. A certain number of respondents are drawn by lottery (including machine lottery or dice). Conduct an actual survey of the selected survey objects.
This method can be used when the total number of respondents is not very large and the individual differences of respondents are small. For example, if an enterprise wants to select 20 products from 100 users and investigate their opinions on product quality and service, it can number1-100 users as 00 100, and then draw10 numbers from them by lottery.
2. Stratified random sampling method: the respondents are grouped (stratified) according to different characteristics, and then a certain number of address samples are randomly selected in each layer. There are two principles in using this sampling method: when layering, there should be obvious differences between layers; each individual in each layer should maintain the neutrality, so as to ensure that the samples extracted from each layer can accurately represent this layer. When the individual differences among the interviewees are large,
3. Grouping random sampling method: divide all similar parts of the respondents into several groups, and then enter one or two groups.
Conduct a random sampling survey. In practice, when there are too many individuals in the survey population and their positions are scattered, the simple random sampling method can effectively reduce this difficulty.
For example, to investigate the family income of workers in a city, we can divide the city into several districts by random sampling, then divide one district into several streets, and concentrate the investigation on two streets in a certain district, so that the cost and time of investigation will be greatly reduced. When the individuals in the survey population are very different, it is impossible to establish the grade standard, and they can only be grouped according to their regions, the method of grouping random sampling can be adopted.
But there are two principles to pay attention to: ① When grouping, try to make all groups have the same characteristics. ② Within each group, there must be great differences among the individuals surveyed.