Linear vs Non-Linear Regression 🔄
Regression analysis can be classified based on the nature of the relationship between the variables. The two main types are Linear and Non-Linear (Curvilinear) Regression.
Classification 🌳
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1. Linear Regression 📏
Definition: If the relationship between two variables can be described by a straight line, it is called Linear Regression.
- Graph: When plotted on a scatter diagram, the points tend to cluster around a straight line.
- Change: For a unit change in the independent variable, there is a constant change in the dependent variable.
Equation
The standard equation for simple linear regression is:
Y = a + bX
Where:
Y= Dependent VariableX= Independent Variablea= Y-interceptb= Slope of the line
2. Non-Linear (Curvilinear) Regression 🎢
Definition: If the relationship between variables is best described by a curve rather than a straight line, it is called Non-Linear or Curvilinear Regression.
- Graph: The points on a scatter diagram cluster around a curve (like a parabola).
- Change: For a unit change in the independent variable, the change in the dependent variable is not constant; it varies depending on the value of X.
Examples
- Growth Curve: Bacteria growth over time (starts slow, speeds up).
- Returns to Scale: Output increases at a diminishing rate as input increases.
Key Differences 📊
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Which one to use? 🤷♂️
In Business Statistics (B.Com level), we primarily focus on Simple Linear Regression because:
- Many business relationships are approximately linear within a certain range.
- It works as a good starting point for analysis.
- Calculations are manageable without advanced software.
[!TIP] Visual Check: Always draw a Scatter Diagram first! If the dots look like a line, use Linear. If they look like a banana or a U-shape, use Non-Linear.
Summary
- Linear: Straight line, constant change.
Y = a + bX. - Non-Linear: Curved line, varying change. used for complex phenomena.
- Business statistics mostly deals with linear relationships for simplicity and estimation.
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