SAT Two-variable data: models and scatterplots Practice Question 7 (Medium)

Question bank / Two-variable data: models and scatterplots

Math · Problem-Solving and Data AnalysisMedium

The line of best fit for a scatterplot passes through the points $(2, 31)$ and $(10, 7)$ . Based on the line of best fit, what is the predicted value of $y$ when $x = 6$ ?

$13$

$16$

$22$

$19$

Show answer and explanation

Answer: D

The slope is $\frac{7 - 31}{10 - 2} = \frac{-24}{8} = -3$ . From $(2, 31)$ , moving $4$ units to $x = 6$ changes $y$ by $4(-3) = -12$ , so the predicted value is $31 - 12 = 19$ . (Since $6$ is the midpoint of $2$ and $10$ , $19$ is also the average of $31$ and $7$ .)

Choice A comes from writing the line as $y = -3x + 31$ , treating the point $(2, 31)$ as if it were the $y$ -intercept.

Ask Owl about this question Next question

Got it wrong? On SAT Owl, Owl looks at the answer you chose and explains the exact mistake, then gives you similar questions until it sticks. Get your predicted SAT score free.