Chapter 7
Correlation1

So far in this book, we have limited ourselves to looking at only one variable at a time, trying to learn as much as possible about that single variable. However, most of our data is made up of many variables, all interacting and having effects on each other. In this chapter you will explore relationships between two variables using graphical methods (scatterplots), computational methods (correlation), and algebraic methods (equations of functions).

As a result of this chapter, students will learn

As a result of this chapter, students will be able to

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How to read and interpret a scatterplot

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How correlation describes the relationship between two variables

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The meanings of ”positive” and ”negative” relationships between two variables

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About the slope and y-intercept of straight lines and how to compute these

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Identify variables with a positive or negative relationship using the correlation coefficient

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Construct a correlation table to determine which variable relationships are most influential

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Estimate the correlation coefficient of two variables based on a scatterplot

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Set up a scatterplot according to conventions about axes, etc.

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Add trendlines to a scatterplot

 7.1 Picturing Two Variable Relationships
  7.1.1 Definitions and Formulas
  7.1.2 Worked Examples
  7.1.3 Exploration 7A: Predicting the Price of a Home
 7.2 Fitting a Line to Data
  7.2.1 Definitions and Formulas
  7.2.2 Worked Examples
  7.2.3 Exploration 7B: Adding Trendlines
 7.3 Homework
  Mechanics and Techniques Problems
  Application and Reasoning Problems
 7.4 Memo Problem: Truck Maintenance Analysis