Quinn is investigating how long his phone's battery lasts (in hours) for various brightness levels (on a scale of 0-100). His data is displayed in the table and graph below.

Brightness Level (x)1940525271727598Hours (y)6.76.24.95.121.842.110

20

30

40

50

60

70

80

90

100

110

1

2

3

4

5

6

7

8

9

10

-1

Brightness Level

Hours

a) Find the equation for the line of best fit. Keep at least 4 decimals for each parameter in the equation.

b) Interpret the slope in context.

• Quinn should expect -0.0703 hours per brightness level.
• Quinn should expect -0.0703 brightness level per hour.

c) What does the equation predict for the number of hours the phone will last at a brightness level of 75?

hours

d) What is theresidualfor the point (75,4)?

hours