关于组中值和序时平均数计算方法的思考

Thoughts on how to Calculate Class Midpoint and Chronological Average

组中值与序时平均数是统计学中的两个重要概念。计算组中值时,不能不加分析地代用其基本公式,而应该根据变量的特点和实际情况作具体处理;根据时点数列求序时平均数,无论其限定词表示的时间长短,都表示求每个时点的平均数值,只是,已知资料的详细程度不同,需采用不同的计算方法。

Class midpoint and chronological average both are one of the most important concepts in statistics. To calculate class midpoint ,it is not as easy as to pick up the formula and then use it. The characteristics of the variables and the situation should be put into the consideration. To use the moment series to calculate the chronological average,no matter how long the time range is limited,it represents the average of every moment. However, a specific method should be used if the degree of population is different.