Paper sample refers to the questionnaire survey sample in paper survey, and the sample size has a great influence on the accuracy of the survey. To a certain extent, the more samples the better, but after all, it is a sampling survey, which means that the representative samples represent the whole. If we can really do a census, we don't need a sampling survey. Generally speaking, if the sample size is large, the sampling error of sampling survey will be reduced. However, how much sample size and sampling error should be chosen to meet the actual needs of the survey and effectively control the cost. Scientifically speaking, intuitively speaking, different research results can be obtained by using different numbers of samples.