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, 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.

Question

(1 point)
• The average final grade is 27% 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 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 based on the number of hours spent on social media, we can use the given equation of the trend line:

\[ y = -7.2x + 98.9 \]

Here, \( x \) is the number of hours spent on social media. We need to predict \( y \) for \( x = 10 \):

1. Substitute \( x = 10 \) into the equation: \[ y = -7.2(10) + 98.9 \]

2. Calculate \( -7.2(10) \): \[ -7.2 \times 10 = -72 \]

3. Now substitute this value back into the equation: \[ y = -72 + 98.9 \]

4. Finally, calculate \( -72 + 98.9 \): \[ y = 26.9 \]

Therefore, to the nearest whole number, if a student spent 10 hours on social media, the average final grade percentage is approximately 27%.

So the correct answer is:

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