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 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 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 7.2 if a student spent 10 hours on social media.

Answer 1

To predict the average final grade percentage when a student spends 10 hours on social media, we can substitute \( x = 10 \) into the provided equation of the trend line:

\[ y = -7.2x + 98.9 \]

Substituting \( x \) with 10:

\[ y = -7.2(10) + 98.9 \]

Calculating this step-by-step:

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

2. Add this to 98.9: \[ y = -72 + 98.9 = 26.9 \]

Rounding \( 26.9 \) to the nearest whole number gives \( 27 \).

Thus, the predicted average final grade percentage, if a student spent 10 hours on social media, is:

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