sum of squares within classes

例句：

1. 1. The sum of squares within classes is used to calculate the average of a set of data.
   类内平方和用于计算一组数据的平均值。
2. 2.In statistics, the sum of squares within classes is often used to test for normality.
   在统计学中，类内平方和通常用于检验数据的正态性。
3. 3.The sum of squares within classes is calculated by adding up all the squared differences between each pair of values in the dataset.
   类内平方和是通过将所有数据集中的每对值的平方差相加来计算的。