The records are treated as a sample of data. That means that the children in the example represent a cross section of all children. Note that a representative result can not be obtained from a sample of less than one thousand.
记录被视为一个数据抽样。这表示示例中的孩子代表所有孩子中的一种典型情况。值得注意的是，如果抽样的数据少于一千个，则无法获得具有代表性的结果。