Line of Best Fit

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

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

Which line appears to fit the data better?

• line A

• line B

Find the equation of the line of best fit for the given data

• y = 163.41x+1.49

• y =- 163.41x+ 4.19

• y =- 4.19x+163.41

• y = 4.19x -163.41

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

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

• Graph A

• Graph B

• Graph C

• Graph D

• 617.51 miles

• 621.09 miles

• 100 miles

• 0.19 miles

Write the linear regression equation for the following data points. Round to the nearest hundredth.

The red line represents the line of best fit for the scatter plot. How many ice cream sales are expected if the temperature is 90°?

• 55

• 0

• 103

• 100

What does the value, r= -0.89, tell us about the linear relationship of two quantitative variables?

• Strong positive

• Weak positive

• Strong negative

• Weak negative