变异，指标一般是标准差、方差、变异系数。

变异性，用变异系数衡量

变异性，是指参数的变化性，用变异系数度量

波动率，就是统计数据的标准差！

大家说的都很好，但最佳答案只有一个，我查了一下google得到以下：
What is variability of a set of numerical data?
Answer ：
Variability is determined by the how numbers are distributed across the set of numbers. There are several ways of measuring this the most common is standard deviation. To find standard deviation you first find the average of the set by adding them all up and dividing by the amount of numbers in the set. Then you find the square of each number in the set minus the average. You add all these values up, multiply them by 1/the number of items in the set, and take the square root. As an example the set {2,5,3,6} has much less variability as measured by the standard deviation than {2000,-1000,-500,484} even though they both have the same average. The firsts average is (2+5+3+6)/4 or 4. The standard deviation is
the square root of(((2-4)^2+(5-4)^2+(3-4)^2+(6-4)^2)*1/4) or about
1.58113883. The standard deviation of the second set that has the same average as the first is the square root of (((2000-4)^2+(-1000-4)^2+(-500-4)^2+(484-4)^2)*1/4) or 1170.09059.
我想参数估计的variability也是差不多的吧。所以我选trier2006 同学