Equation1:s =1/n [(x1-1)+(x2-x)+(x3-x)+...+(xn-x)], where x represents the average number of samples and n represents the number of samples. Equation 2: s = (x1+x2+x3+...+xn)/n-(x1+x2+x3+...+xn)/n, where x is the data in this set of data and n is an integer greater than 0.

Variance formula is an important formula in mathematical statistics, which is applied to all kinds of things in life. When the data distribution is scattered, that is, the data fluctuates greatly near the average value, the sum of squares of the differences between each data and the average value is large and the variance is large. When the data distribution is concentrated, the sum of squares of the differences between each data and the average value is very small. Therefore, the greater the variance, the greater the data fluctuation, the smaller the variance and the smaller the data fluctuation. Variance is the square of variance of each variable value and the average of its mean, which is the most important method to measure the dispersion degree of numerical data.