Statistics for CSAI

by Albert Major

1. Research Design Concepts

Independent vs. Dependent Variables

• Independent Variable (IV): A factor that is manipulated or categorized to observe its effect on another variable. Sometimes called a "predictor" or an "explanatory variable."
• Dependent Variable (DV): The outcome being measured, sometimes called an "outcome variable" or a "response variable."
• Example: In a study on physical activity and weight gain:
  • IV: Activity level.
  • DV: Weight gain.

Confounding Variables

• Definition: A variable that is related to both the independent and dependent variables, potentially distorting the observed relationship.
• Example: If studying the effect of exercise on weight loss, diet and age might be confounding variables.

Discrete vs. Continuous Variables

• Discrete Variable: A variable with specific, separate values (e.g., number of students in a class, rankings).
• Continuous Variable: A variable with an infinite number of possible values within a range (e.g., height, weight, temperature).

2. Measurement Scales

Nominal Scale

• Definition: Categorization without order or ranking.
• Examples: Eye color, gender, diet type (vegetarian, vegan, omnivore).

Ordinal Scale