ORI Curriculum Examples




Case example for Independent and Dependent variables

Definition : A variable is either a result of some force or it is the force that causes a change in another variable. In experiments, these are called dependent and independent variables respectively.

In an experimental study looking at classical music exposure and reading ability in children, the researcher divided the children into two groups (Groups A and B). In Group A, the children listened to Mozart for one hour every day for one month. In Group B, parents were instructed to refrain from playing classical music around the child for one month. At the end of the month, all children were given a reading comprehension test. Those who listened to Mozart daily (Group A) scored significantly higher on the reading test. In this case, the reading comprehension test score is the dependent variable and exposure to Mozart’s music is the independent variable.  This is because the test score is dependent on whether or not the child listens to Mozart’s music. The independent variable, exposure to Mozart’s music, is independent  because it is something that can be manipulated or changed by the researcher.

 In a study with a similar design as the previous example, researchers looked at the effects of nutrition on reading ability. In Group A, children ate at least three ounces of dark green vegetables every day for one month. In Group B, children were fed their regular diet.   At the end of the month, the children took a reading comprehension test. Those who ate the green vegetables every day for one month (Group A) did not vary in their test scores when compared to Group B.

Discussion questions

1. In the second example what is the independent variable? Why?

2. In the second example, what is the dependent variable? Why?

3. Identify which variables are independent and dependent in the following examples:

  • Positive feedback and self confidence
  • Headache and aspirin
  • Muscle mass and weight-training
  • Calcium consumption and bone density
  • Blood pressure and salt intake