Final answer:
A variable that cannot have its exact value predicted in advance is a random variable. Variables can be either numerical, which can be used in calculations, or categorical, which represent various categories. In scientific experiments, the outcome variable affected by another variable is termed the dependent variable.
Step-by-step explanation:
A variable is a random variable if the exact value of the variable cannot be predicted in advance. In mathematics and economics, a variable represents a quantity that can take on different values.
For instance, in the equation of a straight line, such as y = mx + b, the letters x and y denote variables where x represents values on the horizontal axis and y on the vertical axis. While b is the y-intercept and m is the slope of the line, both of which are constant factors.
Variables can be either numerical or categorical. A numerical variable, like the number of points a student earns, can be used in mathematical calculations such as finding an average.
In contrast, a categorical variable, such as a person's party affiliation, cannot be used in the same mathematical calculations because it represents categories rather than numerical values. In a scientific experiment, a 'dependent variable' is the outcome influenced by another variable known as the 'independent variable'.