Society of Actuaries (SOA) PA Practice Exam

What is the primary use of the dummyVars function in R?

1. To create continuous variables

2. To create dummy variables for categorical data

3. To create normalized datasets

4. To handle missing values

The correct answer is: To create dummy variables for categorical data

The dummyVars function in R is primarily used to create dummy variables for categorical data. When working with categorical predictors in statistical models, many modeling techniques require these variables to be converted into a numerical format. Dummy variables help in this conversion by generating binary (0/1) variables that indicate the presence or absence of a particular category. For example, if you have a categorical variable representing "Color" with categories such as "Red," "Blue," and "Green," the dummyVars function would create separate binary variables for each color. This allows regression models and other machine learning algorithms to interpret categorical information in a numerical format which is crucial for analysis. The other options do not accurately describe the primary function of dummyVars. Continuous variables are not created by this function, nor is it designed for normalizing datasets or handling missing values, which are tasks addressed by different functions in R. Thus, the emphasis of the dummyVars function is specifically on transforming categorical data into dummy variables, making it a fundamental tool in data preprocessing for statistical modeling and analysis.