中文：

方差是用来衡量一组数据离散程度的统计量，通常情况下，方差越大，说明数据越离散，反之，方差越小，数据越集中。那么，方差什么时候最小呢？

在一组数据中，如果有一些数据特别大或者特别小，那么这组数据的方差就会比较大。但是，如果所有数据都差不多，或者说数据分布比较均匀，那么方差就会比较小。

此外，方差的最小值并不是一个固定的数值，而是会随着数据的变化而变化。如果一组数据中有一些数据非常接近平均值，那么这组数据的方差就会比较小。

在实际应用中，我们通常会使用平均数来描述一组数据的集中趋势，而使用方差来描述一组数据的离散程度。通过对方差进行分析，我们可以了解数据的分布情况，以及是否存在异常值等问题。

英文：

Variance is a statistic used to measure the degree of dispersion of a set of data. Typically, a higher variance indicates that the data is more scattered, while a lower variance indicates that the data is more concentrated. So when is the variance smallest?

In a set of data, if some values are particularly large or small, the variance of the data will be relatively high. However, if all the values are similar, or the distribution of data is relatively uniform, the variance will be relatively small.

Moreover, the minimum value of variance is not a fixed value, but changes with the data. If a set of data has some values that are very close to the average, the variance of the data will be relatively small.

In practical applications, we usually use the average to describe the central tendency of a set of data, while using the variance to describe the degree of dispersion of the data. By analyzing the variance, we can understand the distribution of data, as well as whether there are any outliers or other issues.