Understanding the Role of Independent and Dependent Variables

In an Experiment, the independent variable is the characteristic manipulated by the researcher to gauge the effect of the changes on the dependent variable. 

Note that the resulting change in the dependent variable is always measured by altering the independent variable. 

Here we will look into several dependent and independent variables in research examples.

 IV and DV examples 1: Assessing the impact of exposure to classical music on math scores.  

You want to determine the effect of exposure to classical music on the test scores on math. 

To see the changes in the test score, divide students into two groups. 

• Students in Group A listened to classical music for an hour every day for two months. 
• Students in Group B were not instructed to listen to classical music. 

After two months, students of both groups were given a math test. It was seen that Group A performed better than Group B. 

In the experiment, test score in math exam was the dependent variable, and the exposure or lack thereof to classical music was the independent variable. 

In an Experiment, while the most common study has one independent variable and one dependent variable, it is also possible to have a different level of each variable. 

• As a researcher, you may want to learn how a single Independent Variable can impact two different dependent variables. 

IV and DV example 2: Investing the impact of video games on teenagers’ memory and mood.

For example, you run an experiment to learn how playing video games impacts a teenager’s memory as well as their mood. In the experiment, while playing video games is your independent variable, the teenager’s memory and mood are your two dependent variables. 

• Similarly, independent variables can have different levels. In some experiments, you may need to use multiple independent variables to see the various effects it may have on the single dependent variable.

IV and DV example 3: Observing the effect of a healthy diet on weight loss.

For example, you want to see how a healthy diet can help with weight loss. So, you will look for several types of a healthy diet and their impact on weight. In this case, different types of diet would be your different levels of the independent variable, while weight loss is the outcome that makes it the dependent variable. 

• Applying two levels of IV can tell you if it affects the DV.
• Applying multiple levels of IV can show you how it influences the outcome of DV. 
• In some cases of experimental research, it is not possible to change the independent variable. 

IV and DV example 4: Assessing the impact of age on weight gain.

In this example, you want to observe if there is any cause-and-effect relationship between age and weight gain. 

• Age is your Independent Variable
• Weight gain is your Dependent Variable

The dependent and independent variables in this research example differ slightly. Here, you cannot control the age of the people you are studying to understand its impact on weight gain. 

So, you compare the factors that had an effect on weight and the factors that did not. Comparing the difference in the other factors, you can learn the changes in a person’s weight caused by their age.