IGCSE Scatter Plots, Correlation and Line of Regression: Complete Guide for Cambridge IGCSE Mathematics

IGCSE scatter plots, correlation and line of regression are essential statistics topics in Cambridge IGCSE Mathematics that appear in both Paper 2 and Paper 4. Mastering drawing scatter plots, identifying correlation, and line of best fit is essential for analyzing relationships between variables.

This comprehensive IGCSE scatter plots, correlation and line of regression guide covers everything you need to know, including drawing scatter plots, identifying positive/negative/no correlation, drawing line of best fit, worked examples, common exam questions, and expert tips from Tutopiya’s IGCSE maths tutors. We’ll also show you how to avoid the most common mistakes that cost students valuable marks.

🎯 What you’ll learn: By the end of this guide, you’ll know how to draw scatter plots, identify correlation types, draw line of best fit, and apply these skills to analyze data relationships in IGCSE exams.

Already studying with Tutopiya? Practice these skills with our dedicated IGCSE Statistics practice deck featuring exam-style questions and instant feedback.

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Why IGCSE Scatter Plots, Correlation and Line of Regression Matter

IGCSE scatter plots, correlation and line of regression are essential statistics topics. Here’s why they’re so important:

• High frequency topic: Scatter plot questions appear regularly in IGCSE maths papers
• Foundation skill: Essential for understanding relationships between variables
• Exam weight: Typically worth 5-8 marks per paper
• Real-world applications: Used in research, science, and data analysis
• Problem-solving skills: Develops data interpretation and analysis abilities

Key insight from examiners: Students often struggle with identifying correlation types or drawing accurate lines of best fit. This guide will help you master these systematically.

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Understanding Scatter Plots

A scatter plot shows the relationship between two variables by plotting points on a graph.

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Types of Correlation

Positive Correlation

As one variable increases, the other also increases. Points trend upward.

Example: Height and weight (taller people tend to weigh more)

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Negative Correlation

As one variable increases, the other decreases. Points trend downward.

Example: Temperature and heating costs (warmer = lower heating costs)

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No Correlation

No clear relationship. Points are scattered randomly.

Example: Shoe size and intelligence (no relationship)

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Drawing Scatter Plots

Steps:

1. Label axes with variable names
2. Choose appropriate scales
3. Plot each data point
4. Identify correlation type

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Line of Best Fit

Line of best fit is a straight line that best represents the data trend.

Method:

• Draw line through the middle of the points
• Roughly equal number of points above and below
• Line should follow the general trend

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Using Line of Best Fit

Use the line to make predictions (interpolation or extrapolation).

Example: Use line of best fit to estimate value when x = 15.

Solution: Find x = 15 on graph, read corresponding y-value from line.

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Common Examiner Traps

• Correlation confusion - Positive: upward trend; Negative: downward trend
• Line of best fit errors - Line should go through middle of points
• Prediction errors - Interpolation (within data range) is more reliable than extrapolation

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Practice Questions

Question 1

A scatter plot shows points trending upward. What type of correlation?

Solution: Positive correlation (as x increases, y increases)

Answer: Positive correlation

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Frequently Asked Questions About IGCSE Scatter Plots, Correlation and Line of Regression

What is a scatter plot?

A scatter plot is a graph showing the relationship between two variables by plotting points.

What is positive correlation?

Positive correlation means as one variable increases, the other also increases (upward trend).

What is negative correlation?

Negative correlation means as one variable increases, the other decreases (downward trend).

What is a line of best fit?

A line of best fit is a straight line that best represents the trend in the data points.

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Related IGCSE Maths Resources

Strengthen your IGCSE Mathematics preparation with these comprehensive guides:

• IGCSE Methods of Analysing Data: Complete Guide - Master data analysis
• IGCSE Statistical Charts: Complete Guide - Master data representation
• IGCSE Maths Revision Notes, Syllabus and Preparation Tips - Complete syllabus overview, topic breakdown, and revision strategies
• IGCSE Past Papers Guide - Access free IGCSE past papers and exam resources

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Next Steps: Master IGCSE Scatter Plots, Correlation and Line of Regression with Tutopiya

Ready to excel in IGCSE scatter plots, correlation and line of regression? Our expert IGCSE maths tutors provide:

• Personalized 1-on-1 tutoring tailored to your learning pace
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Book a free IGCSE maths trial lesson and get personalized support to master scatter plots and achieve your target grade.

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