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.