Disgusting data analysis:
Standard deviation can reflect the degree of dispersion of a data set. The variance unit is inconsistent with the data unit and cannot be used. The standard deviation is consistent with the unit of the data, which is convenient to use.
Dataset: [2, 3, 4, 5, 6]
1: Find the average
(2+3+4+5+6)/5 = 20/5 = 4
2: Find the sum of the squares of the difference between each number and the mean
(2-4)^2 + (3-4)^2 + (4-4)^2 + (5-4)^2 + (6-4)^2 = 10
3: Use the value of the sum of the squares of the differences / the number of data = find the variance
10/5 = 2
4: Variance arithmetic square root = standard deviation std
std = √2
I think the standard deviation was invented to describe the fluctuation of the data