Formulas:

Population Mean:

\[\mu=\frac{\Big(\sum_{i=1}^nx_i\Big)}{n}\]

Sample Mean:

\[\overline{x}=\frac{\Big(\sum_{i=1}^nx_i\Big)}{n}\]

Midrange:

\[\text{MR}=\frac{b+B}{2}\]

Weighted Mean:

\[\overline{X}=\frac{\Big(\sum_{i=1}^nw_i\cdot x_i\Big)}{\sum w}\]

Range:

\[R=B-b\]

Population Variance:

\[\sigma^2=\frac{\Big(\sum_{i=1}^n(x_i-\mu)^2\Big)}{n}\]

Population Standard Deviation:

\[\sigma=\sqrt{\sigma^2}=\sqrt{\frac{\sum_{i=1}^n(x_i-\mu)^2}{n}}\]

Sample Variance:

\[s^2=\frac{\Big(\sum_{i=1}^n(x_i-\overline{x})^2\Big)}{n-1}\]

Sample Standard Deviation:

\[s=\sqrt{s^2}=\sqrt{\frac{\sum_{i=1}^n(x_i-\overline{x})^2}{n-1}}\]

Coefficient of Variance (population):

\[\text{CVar}=\frac{\sigma}{\mu}\cdot 100\]

Coefficient of Variance (sample):

\[\text{CVar}=\frac{s}{\overline{x}}\cdot 100\]