Learn on PengiBig Ideas Math, Algebra 1Chapter 4: Writing Linear Functions

Lesson 5: Analyzing Lines of Fit

Property.

Section 1

Analyzing Lines of Fit

Property

A line of fit (or regression line) is a straight line that best represents the overall trend in a scatterplot. When analyzing a line of fit, we examine how well it models the relationship between two variables by looking at how closely the data points cluster around the line. The line can be used to identify patterns, make predictions, and understand the strength of the relationship between variables.

Examples

Section 2

Residuals and Residual Analysis

Property

A residual is the difference between an actual data point and the predicted value from a line of fit:

residual=yactualypredicted\text{residual} = y_{\text{actual}} - y_{\text{predicted}}

Residual plots display points (x,residual)(x, \text{residual}) to analyze model quality.

Examples

Section 3

Linear Regression Using Technology

Property

Linear regression on a graphing calculator finds the line of best fit y=ax+by = ax + b and correlation coefficient rr by entering data into lists and using the LinReg function to calculate optimal parameters.

Examples

Section 4

Interpolation

Property

Using a regression line to estimate values between known data points is called interpolation.

Examples

Cocoa sales data is collected for temperatures between 22^\circC and 1818^\circC. Using the regression line C=2.5T+52C = -2.5T + 52 to predict sales at 99^\circC is interpolation. We get C=2.5(9)+52=29.5C = -2.5(9) + 52 = 29.5 cups.

A baby whale's length is recorded at birth (0 months) and 7 months. Using a linear model to estimate its length at 4 months is interpolation, because 4 is between 0 and 7.

Book overview

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Chapter 4: Writing Linear Functions

  1. Lesson 1

    Lesson 1: Writing Equations in Slope-Intercept Form

  2. Lesson 2

    Lesson 2: Writing Equations in Point-Slope Form

  3. Lesson 3

    Lesson 3: Writing Equations of Parallel and Perpendicular Lines

  4. Lesson 4

    Lesson 4: Scatter Plots and Lines of Fit

  5. Lesson 5Current

    Lesson 5: Analyzing Lines of Fit

  6. Lesson 6

    Lesson 6: Arithmetic Sequences

  7. Lesson 7

    Lesson 7: Piecewise Functions

Lesson overview

Expand to review the lesson summary and core properties.

Expand

Section 1

Analyzing Lines of Fit

Property

A line of fit (or regression line) is a straight line that best represents the overall trend in a scatterplot. When analyzing a line of fit, we examine how well it models the relationship between two variables by looking at how closely the data points cluster around the line. The line can be used to identify patterns, make predictions, and understand the strength of the relationship between variables.

Examples

Section 2

Residuals and Residual Analysis

Property

A residual is the difference between an actual data point and the predicted value from a line of fit:

residual=yactualypredicted\text{residual} = y_{\text{actual}} - y_{\text{predicted}}

Residual plots display points (x,residual)(x, \text{residual}) to analyze model quality.

Examples

Section 3

Linear Regression Using Technology

Property

Linear regression on a graphing calculator finds the line of best fit y=ax+by = ax + b and correlation coefficient rr by entering data into lists and using the LinReg function to calculate optimal parameters.

Examples

Section 4

Interpolation

Property

Using a regression line to estimate values between known data points is called interpolation.

Examples

Cocoa sales data is collected for temperatures between 22^\circC and 1818^\circC. Using the regression line C=2.5T+52C = -2.5T + 52 to predict sales at 99^\circC is interpolation. We get C=2.5(9)+52=29.5C = -2.5(9) + 52 = 29.5 cups.

A baby whale's length is recorded at birth (0 months) and 7 months. Using a linear model to estimate its length at 4 months is interpolation, because 4 is between 0 and 7.

Book overview

Jump across lessons in the current chapter without opening the full course modal.

Continue this chapter

Chapter 4: Writing Linear Functions

  1. Lesson 1

    Lesson 1: Writing Equations in Slope-Intercept Form

  2. Lesson 2

    Lesson 2: Writing Equations in Point-Slope Form

  3. Lesson 3

    Lesson 3: Writing Equations of Parallel and Perpendicular Lines

  4. Lesson 4

    Lesson 4: Scatter Plots and Lines of Fit

  5. Lesson 5Current

    Lesson 5: Analyzing Lines of Fit

  6. Lesson 6

    Lesson 6: Arithmetic Sequences

  7. Lesson 7

    Lesson 7: Piecewise Functions