Slope and Y-Intercept of the Line of Best Fit

Which of the following lines represents the line of best fit for the scatter plot?

• A

• B

• C

• D

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 a LINE OF BEST FIT passes through the points (4, 8) and (6, 2). The SLOPE of this line is . . .?

• -3

• -6

• 4

• 2

Suppose a LINE OF BEST FIT passes through the points (4, 8) and (6, 2). The Y-INTERCEPT of this line is . . .? (hint: find the equation in point-slope form first and then put it into slope-intercept form)

• 11

• 4

• 9

• 20

A scientist is studying the relationship between the amount of sunlight a plant receives (x) and its growth rate (y). He finds the equation of the line of best fit to be:

y = 0.59x - 21.912

What is the rate of growth of the plant for each unit increase in sunlight?

• 0.59

• 0.59x

• 21.912

• -21.912

the slope is -5/7, what does that mean?

• gain 5 hour of sleep for 7 cups of coffee

• lose 5 hours of sleep for 7 cups of coffee

• lose 7 cups of coffee for 5 hours of sleep

• lose 5 cups of coffee for 7 hours of sleep

A scientist is studying the rate of a chemical reaction. He plots a graph and finds the line of best fit to be:

y = -0.011x + 40.604

Here, 'y' represents the concentration of the product and 'x' represents time. What is the rate of the reaction (slope of the line of best fit)?

• 0.011

• -0.011

• -0.011x

• 40.604

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

The scatterplot shows data collected from 9 people about how much money they earned based on the hours they worked. Use 2 points on the line of best fit and find the slope.

Using your slope from the previous question, give the equation for the line of best fit in point-slope form (choose 1 of the 2 points you used to find the slope)