Your teacher surveyed the class to determine the number of hours that each student spent on social media. Your teacher created a table and scatterplot graph that displayed the number of hours, x

Question

, and the average final grade percentage, y
, based on the hours. Using the equation of the trend line of the data, y=–7.2x+98.9
, predict the average final grade percentage, to the nearest whole number, if a student spent 10 hours on social media.(1 point)
Responses

The average final grade is 99% if a student spent 10 hours on social media.
The average final grade is 99% if a student spent 10 hours on social media.

The average final grade is 27% if a student spent 10 hours on social media.
The average final grade is 27% if a student spent 10 hours on social media.

The average final grade is 92% if a student spent 10 hours on social media.
The average final grade is 92% if a student spent 10 hours on social media.

The average final grade is 7.2 if a student spent 10 hours on social media.

Answer 1

To predict the average final grade percentage when a student spent 10 hours on social media using the trend line equation $y=-7.2x+98.9$, we need to substitute $x=10$ into the equation:

$$y=-7.2(10)+98.9$$

Calculating this gives:

$$y=-72+98.9$$ $$y=26.9$$

Rounding to the nearest whole number, we get:

$$y\approx 27$$

Therefore, the average final grade is 27% if a student spent 10 hours on social media.