Teach you to calculate the standard deviation hand in hand, even a novice can understand it at a glance

Standard Deviation is the most commonly used measure in probability statistics as a measure of statistical distribution. The standard deviation is defined as the arithmetic square root of variance, reflecting the degree of dispersion between individuals within a group. The results measured to the degree of distribution generally have two properties: the standard deviation of a total quantity or a random variable, and the standard deviation of a subset of samples. The formula is as follows. The concept of standard deviation was introduced into statistics by Karl Pearson.
The calculation steps for sample standard deviation are:
Step 1: (Subtract the average of all sample data from each sample data).
Step 2, add the squares of the values obtained in Step 1.
Step 3: Divide the result of Step 2 by (n-1) ("n" refers to the number of samples).
Step 4: The square root of the values obtained from Step 3 is the standard deviation of the sampling.
The calculation steps for the overall standard deviation are:
Step 1: (Subtract the average of all population data from each sample data).
Step 2, add the squares of the values obtained in Step 1.
Step 3: Divide the result of Step 2 by n ("n" refers to the total number).
Step 4: The square root of the values obtained from Step 3 is the standard deviation of the population.