What does a contingency table tell you?

What does a contingency table tell you?

A contingency table is a tabular representation of categorical data . A contingency table usually shows frequencies for particular combinations of values of two discrete random variable s X and Y. Each cell in the table represents a mutually exclusive combination of X-Y values.

What are contingency tables useful to analyze?

Contingency tables can be used to summarize probability distributions, namely (a) joint, (b) marginal, and (c) conditional distributions. As you can see from the definitions below, the sum of probabilities in each type of distribution must add up to one, which in statistician thinking is 100 percent.

What scale of measurement is appropriate for two way contingency table analysis?

Contingency tables (also called two-way frequency tables or crosstabs or cross-tabulations) are used to find the relationship (association or dependencies) between two or more variables measured on the nominal or ordinal measurement scale.

What is the purpose of a contingency table?

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.

How do you interpret contingency coefficients?

Understanding Contingency Coefficient Values

1. If C is near zero (or equal to zero) you can conclude that your variables are independent of each other; there is no association between them.
2. If C is away from zero there is some relationship; C can only take on positive values.

What is contingency table in stats?

In statistics, a contingency table (also known as a cross tabulation or crosstab) is a type of table in a matrix format that displays the (multivariate) frequency distribution of the variables. They provide a basic picture of the interrelation between two variables and can help find interactions between them.

Is Gamma a pre measure?

Gamma is a measure of association that measures the Proportional Reduction in Error (PRE) obtained when the researcher uses the value of the independent variable to predict the value of the dependent variable.

What kind of variables are age and height?

Quantitative variables are any variables where the data represent amounts (e.g. height, weight, or age). Categorical variables are any variables where the data represent groups.

How do contingency tables work?

A contingency table provides a way of portraying data that can facilitate calculating probabilities. The table helps in determining conditional probabilities quite easily. The table displays sample values in relation to two different variables that may be dependent or contingent on one another.

What is the function of a contingency table in bivariate analysis?

Contingency Tables The joint distribution of two variables is called a bivariate distribution. A contingency table shows the frequency distribution of the values of the dependent variable, given the occurrence of the values of the independent variable.

How do you find the value of a contingency table?

Consequently, to calculate joint probabilities in a contingency table, take each cell count and divide by the grand total. For our example, the joint probability of females buying Macs equals the value in that cell (87) divided by the grand total (223).

When to use a contingency table in statistics?

The table helps in determining conditional probabilities quite easily. The table displays sample values in relation to two different variables that may be dependent or contingent on one another. Later on, we will use contingency tables again, but in another manner.

Where can I find a contingency table for crime?

Available online at http://www.disastercenter.com/crime/ (accessed May 2, 2013). There are several tools you can use to help organize and sort data when calculating probabilities. Contingency tables help display data and are particularly useful when calculating probabilites that have multiple dependent variables.

What does the bottom row in a contingency table mean?

For data from prospective and experimental studies, the top row usually represents exposure to a risk factor or treatment, and the bottom row is for controls. The left column usually tabulates the number of individuals with disease; the right column is for those without the disease.

When do you need a contingency table in OpenStax?

Contingency tables help display data and are particularly useful when calculating probabilites that have multiple dependent variables. OpenStax, Statistics, Contingency Tables. Provided by: OpenStax. Located at: http://cnx.org/contents/[email protected]:22/Introductory_Statistics.