2x2Kreuztabelle

A 2x2 Kreuztabelle, also known as a 2x2 contingency table or a 2x2 table, is a statistical tool used to display the frequency distribution of two categorical variables, each with two possible outcomes. It is a fundamental concept in statistics, particularly in the analysis of categorical data. The table is structured as a grid with two rows and two columns, creating four cells. Each cell represents the joint frequency of a specific combination of the outcomes of the two variables.

For example, if we are analyzing the relationship between smoking status (smoker/non-smoker) and the occurrence of a certain disease (present/absent), a 2x2 Kreuztabelle would have rows representing smoking status and columns representing disease status. The four cells would then show the number of people who are smokers and have the disease, smokers and do not have the disease, non-smokers and have the disease, and non-smokers and do not have the disease.

The primary purpose of a 2x2 Kreuztabelle is to facilitate the examination of potential associations or relationships between the two variables. By observing the distribution of frequencies across the cells, one can begin to infer whether the two variables are independent or dependent. Various statistical tests, such as the chi-squared test, are commonly applied to data presented in a 2x2 Kreuztabelle to formally assess the statistical significance of any observed association. This simple yet powerful structure is widely used in fields like medicine, social sciences, and market research for initial data exploration and hypothesis testing.