Final answer:
Variables in R can store a variety of data types and can be used in mathematical operations. The options provided in the question do not accurately describe variables in R. Variables can store data, perform operations such as addition, and R does provide output upon variable assignment.
Step-by-step explanation:
The correct statement about variables in R among the options provided is that none of the options given correctly describe how variables work in R. In R, a variable can store data types other than just a single number, including vectors, matrices, lists, and more.
We can indeed add two variables together, provided that the operations make sense. Also, R will typically return the value of the assignment invisibly when you create a variable unless the assignment is wrapped in parentheses, in which case it will print the value. Lastly, variables are used specifically to store information in R, so it is not true to suggest that they cannot store information.
Variables in R, such as X and Y, can be numerical or categorical. Numerical variables can be used to perform math operations like calculating averages. Categorical variables, however, place items into categories and do not typically support numerical calculations. For example, the variable X could represent a numerical value like the number of points earned by a math student, while Y might represent a categorical value like party affiliation.