# Which regression is used for categorical variables?

### Table of Contents

- Which regression is used for categorical variables?
- Can you include categorical variables in regression?
- What is categorical regression?
- What are the 5 types of variables?
- What is an example of Ancova?
- What is the synonym of variable?
- What are the 3 different types of variables?
- How do you correlate two categorical variables?
- How to use coding for categorical variables in regression analysis?
- Why do you use dummy coding for categorical variables?
- How to treat exercise variable as categorical variable?
- Which is the reference level for a categorical variable?

### Which regression is used for categorical variables?

All Answers (13) Categorical variables can absolutely used in a **linear regression model**.

### Can you include categorical variables in regression?

Categorical variables require special attention in regression analysis because, unlike dichotomous or continuous variables, they cannot by entered into the regression equation just as they are. Instead, **they need to be recoded into a series of variables which can then** be entered into the regression model.

### What is categorical regression?

Categorical regression **quantifies categorical data by assigning numerical values to the categories**, resulting in an optimal linear regression equation for the transformed variables. Categorical regression is also known by the acronym CATREG, for categorical regression.

### What are the 5 types of variables?

There are different types of variables and having their influence differently in a study viz. **Independent & dependent variables, Active and attribute variables, Continuous, discrete and categorical variable, Extraneous variables and Demographic variables**.

### What is an example of Ancova?

ANCOVA can control for other factors that might influence the outcome. For example: **family life, job status, or drug use**.

### What is the synonym of variable?

**Synonyms & Antonyms of variable**

- adaptable,
- adjustable,
- alterable,
- changeable,
- elastic,
- flexible,
- fluid,
- malleable,

### What are the 3 different types of variables?

There are three main variables: **independent variable, dependent variable and controlled variables**. Example: a car going down different surfaces.

### How do you correlate two categorical variables?

To measure the relationship between numeric variable and categorical variable with > 2 levels you should use **eta correlation** (square root of the R2 of the multifactorial regression). If the categorical variable has 2 levels, point-biserial correlation is used (equivalent to the Pearson correlation).

### How to use coding for categorical variables in regression analysis?

- From this point we will refer to a coding scheme when used with the
**regression**command as**regression**coding.**Another**method**for**analyzing**categorical**data would be to**use**the glm command and then**you**could**use**the / lmatrix or the / contrast commands to perform comparisons among the levels of the**categorical**variable.

### Why do you use dummy coding for categorical variables?

- Because dummy coding compares the mean of the dependent variable
**for**each level of the**categorical**variable to the mean of the dependent variable at**for**the reference group, it makes sense with a nominal variable. However, it may not make as much sense to**use**a coding scheme that tests the linear effect of race.

### How to treat exercise variable as categorical variable?

- To make sure that R treats the exercise variable as a
**categorical**one**in**our**regression**model we should check**what**R thinks this variable is: Notice R thinks this is a discrete numeric variable (incorrectly). Therefore we should correct this before performing a**regression**. This**can**be done with the as.factor function.

### Which is the reference level for a categorical variable?

- The level of the
**categorical**variable that is coded as zero**in**all of the new**variables**is the reference level, or the level to which all of the other levels are compared.**In**our example, white is the reference level.**You can**select any level of the**categorical**variable as the reference level.