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

Question

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  y
 -intercept. What is the average grade if a student was on social media for 0 hours?(1 point)

GPT-4o mini · Answer

The equation of the trend line is $ y = -7.2x + 98.9 $. In this equation, $ y $ represents the average final grade and $ x $ represents the number of hours spent on social media. The $ y $-intercept occurs when $ x = 0 $. To find the average grade for a student who spent 0 hours on social media, we substitute $ x = 0 $ into the equation: $$ y = -7.2(0) + 98.9 $$ $$ y = 0 + 98.9 $$ $$ y = 98.9 $$ Thus, if a student was on social media for 0 hours, the average grade would be 98.9. **Interpretation of the $ y $-intercept:** The $ y $-intercept of 98.9 indicates that students who do not spend any time on social media (0 hours) are expected to have an average final grade of 98.9. This suggests a positive correlation between time spent on social media and final grades, where less time on social media is associated with higher grades.