The possibility of each individual remaining after the nth sampling by simple random sampling

When analyzing the sampling process, the most important principle is to ensure that the sample can represent the whole population well. The starting point of random sampling is to make every individual have the same chance of being drawn, which is based on the consideration of the representativeness of the sample data. ∫ In simple random sampling, the probability of each individual being drawn is equal, and n has nothing to do with the number of times. \n∴ Answer D is correct, \nSo choose D.. Comment on which sampling to choose. It should be decided according to the overall situation given by the topic. If the overall number of people is small, lottery can be used. If the total number is large, but there is little difference between the parts, systematic sampling can be used. If there is a big difference in the total number of individuals, stratified sampling can be used.