Basic Definitions

General Information on Statistics

Descriptive statistics are mathematical expressions which describe a given data set. Mean, median, and mode are classic examples. These are used to understand a current or past population, but not extrapolate future trends.

Inferential statistics are mathematical models to attempt to extrapolate new information from existing data. Linear regression and trend analysis in general are examples of inferential statistics.

While descriptive statistics can be done on any size data set (though for small sets they aren't as necessary), inferential statistics generally need a relatively larger set to be accurate and useful.

Probabilities run a strange gambit in between describing a data set and potentially inferring future states. Probabilities can move anywhere between describing a coin flip to complex models like Monte-Carlo simulations and Random Forests.