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**Independent variable:** The input variable or the controlled variable (less error / no error)

**Dependent variable:** The output variable or the variable we want to predict (contains error)

**(i)** Temperature \(x\)°C and yield \(y\) kg
• Independent variable: \(x\)°C
• Dependent variable: \(y\) kg

**(ii)** Room air temperature \(x\)°C and thermostat temperature \(C\)
• Independent variable: \(C\)
• Dependent variable: \(x\)

**(iii)** Time practicing \(x\) hours and test score \(y\) marks
• Independent variable: \(x\)
• Dependent variable: \(y\)

**(iv)** IQ score \(x\) and height \(y\) cm
• No observable dependence, more data needed

**(v)** Math test score \(x\) and History test score \(y\)
• No clear independent/dependent relationship

**Scatter Diagrams and Correlation:**
• Positive Correlation: Points trend upward from left to right
• Negative Correlation: Points trend downward from left to right
• Quadratic/Curvilinear: Points follow a curved pattern
• No observable Relation: Points scattered randomly

Worked Example 1

Worked Example 1

Video Solution:

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