Constructing Scatter Plots and Lines of Best Fit

The scatter plot shows the relationship between the number of chapters and the total number of pages for several books.  Use the trend line to predict how many chapters would be in a book with 180 pages. 

• 12 chapters

• 15 chapters

• 18 chapters

• 21 chapters

440 turtles 40 turtles 150 turtles 90 turtles

• 440 turtles

• 40 turtles

• 150 turtles

• 90 turtles

Find the slope for the trend line using points (2,2) and (4,3)

• 2

• 1/2

• -2

• -1/2

Which scatter plot shows a linear relationship between x and y?

• Graph A

• Graph B

• Graph C

• Graph D

Take a look at the scatter plot and line of best fit. Is the line of best fit correct? Why or why not?

• No, while the line does cross through some points, it does not follow the slope of the data.

• Yes, there are approximately the same points above and below the line.

• No, not enough points are plotted to determine if this is an accurate line.

• Yes, the line trends closely with the observed data.

Take a look at the scatter plot and line of best fit at right. Is the line of best fit correct? Why or why not?

• Yes, it falls well within most of the data observed.

• No, most of the data points fall below the line.

• Yes, there are points above and below the line.

• No, the line’s slope does not match the trend of the data.

The scatter plot below shows the number of books read by students in Mrs. Hall’s English class and their final grades. Which statement represents the best description about the line of best fit?

• The more books students read, the lower their English grade.

• The more books students read, the higher their English grade.

• The fewer books students read, the higher their English grade. 

• No relationship exists between the number of books students read and their English grades. 

TRUE OR FALSE: A line of best fit must go through the origin.

• True

• False

As the age of the car increases, its value decreases. Which scatterplot represents this relationship?

• A

• B

• C

• D

What is a line of best fit used for?

• To make predictions

• To make the graph look pretty

• To connect the points

• To make it look like you know what you are doing