Scatterplots and Line of Best Fit Equations

Which of the following could be a possible line of best fit for the data?

• y = -5/2x + 20

• y = -x + 19

• y = x + 20

• y = 2/3x + 15

Suppose data related to the AVERAGE Temperature outside (T) and the number of winter Coats (C) sold at a store is collected and graphed.

The LINE OF BEST FIT has the equation C = -3T + 150.

Use this equation to predict the number of coats sold when the average temperature outside is 20°.

• 40

• 75

• 90

• 115

Suppose a LINE OF BEST FIT passes through the points (6, 34) and (8, 50). The EQUATION of this line is . . .? (hint: find the slope and the equation in point-slope form. THEN put it into slope-intercept form)

• y = 8x – 5

• y = 2x

• y = 2x + 7

• y = 8x – 14

In the scatter plot, does the image shows a "Line of Best Fit"?

• Yes

• No

The graph shows a line of best fit for data collected on the amount of income earned by lawn companies in relation to the number of yards mowed.  What is the equation of the line of best fit?

• y = 30x

• y = 30x + 300

The graph above shows a line of best fit for data collected on the distance bicyclists have remaining in relation to the amount of time they have been riding.  What is the equation of the line of best fit?

• y = -25x + 170

• y = 25x + 170

The graph below shows the value of a computer given the age of the computer. Which equation would best fit the data?

• y = -250x + 2000

• y = 250x + 2000

• y = -250x - 2000

• y = 2000x -250

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.