Question

select the correct answer.
the graph shows a relationship between the average number of hours 15 ninth graders spend studying per week and their grade point average.
which equation best models this data set?

• $y = 1.2x + 0.28$
• $y = 1.2x - 0.28$
• $y = 0.28x + 1.2$
• $y = -0.28x + 1.2$

Explanation:

Step1: Identify y-intercept trend

The line crosses the y-axis near $y=1.2$, so the constant term is ~1.2.

Step2: Check slope sign

Data has positive correlation, so slope is positive. Eliminate negative slope option.

Step3: Calculate approximate slope

Use points $(0,1.2)$ and $(8,3.3)$:
$\text{slope} = \frac{3.3 - 1.2}{8 - 0} = \frac{2.1}{8} = 0.2625 \approx 0.28$

Step4: Match to equation

Slope ~0.28, y-intercept ~1.2, so equation is $y=0.28x+1.2$.

Answer:

$y = 0.28x + 1.2$