# Statistics Formulas

Statistics is a branch of mathematics which deals with numbers and data analysis. Statistics is the study of the collection, analysis, interpretation, presentation, and organization of data. Statistical theory defines a statistic as a function of a sample where the function itself is independent of the sample’s distribution.

In short, Statistics is associated with collecting, classifying, arranging and presenting numerical data. It allows us to interpret various results from it and forecast many possibilities. Statistics deals with facts, observations and information which are in the form of numeric data only. With the help of statistics, we are able to find various measures of central tendencies and the deviation of different values from the center.

## Statistics Formula Sheet

 Mean $bar{x}=\frac{\sum x}{n}$ x = Items given n = Total number of items Median If n is odd, then M = $(\frac{n+1}{2})$$^{th}$ term If n is even, then M = $\frac{(\frac{n}{2})^{th}term+(\frac{n}{2}+1)^{th}term}{2}$ n = Total number of items Mode The value which occurs most frequently Variance $\sigma ^{2}$ = $\frac{\sum (x-bar{x})^{2}}{n}$ x = Items given $bar{x}$ = Mean n = Total number of items Standard Deviation $S = \sigma = \sqrt{\frac{\sum (x-bar{x})^{2}}{n}}$ x = Items given $bar{x}$ = Mean n = Total number of items