We explain what the dependent and independent variables are and the relationship between them. Additionally, quantitative and qualitative variables.
What are dependent and independent variables?
Variables are symbols that represent some type of indeterminate quantity or factor, that is, it can vary, which is not fixed. It is the opposite, in that sense, to a constant. When they are mathematical symbols, they are usually represented with letters (x, y), but they can also be logical or of another nature.
Among variables, independent variables are those that can take various numerical values (or arguments) and are generally represented as x. The independent variables directly affect the dependent variables (generally and).
The difference between the two has to do with the fact that one depends on the other, and therefore the relationship between the two can be used in a controlled manner to study the way in which said dependence occurs. That is, they can be understood as a cause (x) and effect (and), given that the independent variable is in the hands of the researcher, while the other is not.
Let's try to explain this with an example. If we know that for every hamburger we eat we will have to do two hours of exercise, we can express the relationship between both things mathematically by saying that for every x eaten hamburgers, we will get 2and hours of exercise, since x = 2y.
The independent variable is hamburgers, since we can eat the amount we decide, freely, while the dependent variable will always be the number of hours of exercise, since they arise from the first premise.
Variables of an investigation
Variables are a fundamental aspect of any research or experiment. The way to determine the relationship between the variables that concern us, that is, to propose the beginning of the investigation, is will be known as a hypothesis and consists of particular statements.
Apart from what has already been explained about the dependent and independent variables, we can talk about other possible types of variables:
- Quantitative variables They are those that represent relationships expressible in terms of quantity, that is, quantifiable, countable. They are classified into discreet (the set of all possible values expressed in isolated points) and continuous (intervals between points or possible values within a range).
- Qualitative variables On the contrary, they represent relationships of meaning, property or quality, not expressible numerically. They are further classified into nominal (they serve to name, it has no inherent order or sequence) or ordinal (they obey an ordered series, expressing degrees of the same thing).
Examples of variables
Below we will propose a series of statements in which the independent variables are differentiated (x) of the dependents (and):
- The ozone layer in the atmosphere shrinks by a certain amount (y) with each ton of toxic gases emitted monthly (x).
- Cigarette consumption (x) decreases physical resistance (y).
- We wish to study the impact of yerba mate consumption (x) on the frequency of colon cancer in Uruguayan society (y).
- Experts affirm an inversely proportional relationship between an individual's intelligence (x) and their levels of political fanaticism (y).
- Scientists suspect that a certain type of bacteria reproduces more easily (y) in the presence of some organic alkaloids (x).
Continue with: Scientific research
References
- “Variable” in Wikipedia.
- “Review of dependent and independent variables” in Khan Academy.
- “Research variables” on Explorable.com.
- “When a variable is dependent or independent” (video) in Ciencia Alogiada.
- “How do dependent and independent variables affect experimental research?” in Self-Help Resources.
