If each number is multiplied by a, the current average is ax, the variance is aay, and the standard deviation is az.
If each number is multiplied by a, plus b, the current average is ax+b, the variance is aay, and the standard deviation is az.
Introduction:
Variance is a measure of dispersion when probability theory and statistical variance measure random variables or a set of data. Variance in probability theory is used to measure the deviation between random variables and their mathematical expectations (that is, the mean value).
The variance (sample variance) in statistics is the average value of the square of the difference between each sample value and the average value of all sample values. In many practical problems, it is of great significance to study variance or deviation.