Independent and Dependent Variables
Bivariate Data
- Bivariate data is numerical data that consists of two variables organized into pairs of values.
- It compares two variables.
- Non-bivariate data provides only one numerical data point; an example is favorite ice cream flavor and the number of students who like it.
Cause and Effect
- Bivariate data highlights the relationship between a reason (cause) and its result (effect).
- Example: Continuous rainy season (cause) leads to an increase in umbrella sales (effect).
- Example: Increased price of goods (cause) leads to a decrease in the number of grocery items you can buy (effect).
Independent Variable
- The independent variable is the variable that, when changed, affects the other variable.
- It represents the "cause" in a cause-and-effect relationship.
- Example: Continuous rainy season is the independent variable that causes an increase in umbrella sales.
Dependent Variable
- The dependent variable is the variable whose value depends on the independent variable.
- It represents the "effect" in a cause-and-effect relationship.
- Example: Exam score is dependent on the time (in hours) spent studying.
- 4 hours spent studying results in a score of 84.
- 3 hours spent studying results in a score of 80.
- 6 hours spent studying results in a score of 95.
- 2 hours spent studying results in a score of 76.
- 5 hours spent studying results in a score of 89.
Relationship Between Independent and Dependent Variables
- The number of grocery items you can buy (dependent variable) is affected by the price of goods (independent variable).
Graphing Variables
- The independent variable is placed on the x-axis (horizontal axis).
- The dependent variable is placed on the y-axis (vertical axis).
- Example: Graphing time spent studying (independent variable) vs. score on exam (dependent variable).
Review
- Independent Variable:
- It does not depend on any other variables.
- It is located on the horizontal (x) axis.
- Dependent Variable:
- It depends on the value of the independent variable.
- It is located on the vertical (y) axis.
Real-Life Scenarios
- Consider scenarios where input and output are at play to identify independent and dependent variables.