# Contingency Table

A contingency table is a tabular data item that summarizes frequency distribution statistics of a proper set of categorical variables.

**Context:**- It can be used to used to examine the relationship between two random variables.

**Example(s):**- a 2x2 Contingency Table.
- a 3x3 Contingency Table.
- ...

**Counter-Example(s):**- a Confusion Matrix.
- a Scatterplot.

**See:**Chi Square Test, Contingency Table Analysis

## References

### 2011

- http://en.wikipedia.org/wiki/Contingency_table
- In statistics, a
**contingency table**(also referred to as**cross tabulation**or**cross tab**) is a type of table in a matrix format that displays the (multivariate) frequency distribution of the variables. It is often used to record and analyze the relation between two or more categorical variables.The term

*contingency table*was first used by Karl Pearson in "On the Theory of Contingency and Its Relation to Association and Normal Correlation", part of the*Drapers' Company Research Memoirs Biometric Series I*published in 1904.A crucial problem of multivariate statistics is finding (direct-)dependence structure underlying the variables contained in high dimensional contingency tables. If some of the conditional independences are revealed, then even the storage of the data can be done in a smarter way (see Lauritzen (2002)). In order to do this one can use information theory concepts, which gain the information only from the distribution of probability, which can be expressed easily from the contingency table by the relative frequencies.

- In statistics, a

### 2007

- http://www.eumetcal.org/resources/ukmeteocal/verification/www/english/msg/ver_categ_forec/uos1/uos1_ko1.htm
- QUOTE: A contingency table is essentially a display format used to analyse and record the relationship between two or more categorical variables. It is the categorical equivalent of the scatterplot used to analyse the relationship between two continuous variables. … Since dichotomous (two-category) variables are of special interest in meteorology, the emphasis in this module is on the verification methods for the 2*2 contingency tables used to summarize verification datasets for dichotomous variables. Extensions to verification of variables with three or more categories are discussed in the last unit of the module.