======Commonly used statistical symbols======

Since statistical symbols are often parameters that appear in pairs with statistics, a list of these corresponding symbols is shown below:

^  ^  Parameters (overall)  ^  Statistics (sample)  ^
|  Group size  |  {{ :第一章:1.7:n.svg }}  |  {{ :第一章:1.7:n1.svg }}  |
|  Mean  |  {{ :第一章:1.7:mu.svg }}  |  {{ :第一章:1.7:overlinex.svg }}  |
|  Standard deviation  |  {{ :第一章:1.7:sigma.svg }}  |  {{ :第一章:1.7:s.svg }}  |
|  Variance  |  {{ :第一章:1.7:sigma2.svg }}  |  {{ :第一章:1.7:s2.svg }}  |
|  Correlation coefficient  |  {{ :第一章:1.7:rho.svg }}  |  {{ :第一章:1.7:r1.svg }}  |


Many calculations in statistics require the addition of a series of fractions, so the Greek letter {{:第一章:1.7:sigma1.svg}} is used to represent the sum of a series of fractions. For example, {{:第一章:1.7:sigmax.svg}} represents the sum of all values of the variable {{:第一章:1.7:x.svg}}.