11-4: Linear Models – Fitting a Straight Line

Key Concept

When two sets of data have a positive or negative linear association, you can use a special line, called a trend line, to show the association more clearly.

A trend line is a line on a scatter plot, drawn near the points, that approximates the association between the data sets.

A scatter plot. x-axis: Number of People. y-axis: Cost (dollars). Points: 15 plotted from 1 to 6 on the x-axis and from 9 to 49 on the y-axis. Line: through (0, 12) and (8, 50). The trend line should be as close as possible to each data point. There should be about as many points above the trend line as below it.

Part 1

Example Choosing Reasonable Trend Lines

Which of the lines shown are reasonable trend lines for the scatter plot? Explain your reasoning.

A scatter plot with 3 trend lines


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Table of Contents

Digits, Grade 8, Volume 2, Homework Helper Unit D: Two-Dimensional Shapes Unit E: Measurement and Data Unit F: Personal Financial Literacy Unit G: Step-Up Lessons English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties