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 and the average final grade based on the hours. The trend line (equation) for the data is y=-7.2x+98.9. Interpret the slope. What is the average grade if a student was on social media for 0 hours?
The slope of the trend line, -7.2, represents the rate of change in the average final grade for each additional hour spent on social media.
In this case, the negative slope indicates that as the number of hours spent on social media increases, the average final grade decreases. Specifically, for every additional hour spent on social media, the average final grade decreases by 7.2 points.
If a student was on social media for 0 hours, we can substitute x=0 in the equation y=-7.2x+98.9 to find the average grade:
y = -7.2(0) + 98.9
y = 0 + 98.9
y = 98.9
Therefore, if a student spends 0 hours on social media, the average grade is 98.9.