# Question Video: Using Straight Lines to Model Relationships between Two Quantitative Variables Mathematics • 8th Grade

The following scatter diagram shows the test results of two exams for a class of 26 students. If Sophia got 84 on exam 1, which of the following would you expect to be her score for exam 2? [A] 70 [B] 92 [C] 86 [D] 50 [E] 60

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### Video Transcript

The following scatter diagram shows the test results of two exams for a class of 26 students. If Sophia got 84 on exam one, which of the following would you expect to be her score for exam two?

Here our đť‘Ą-axis graphs what exam one test results are, and where our đť‘Ąs on the đť‘¦-axis shows us what they got on exam two. For example, this first đť‘Ą received a 44 on exam one and a 52 on exam two. This đť‘Ą is in position 44, 52.

We want an estimate for Sophia who received an 84 on exam one. Sophiaâ€™s đť‘Ą-axis would be plotted at 84. Based on the data weâ€™re given and other similar points, we would think that Sophiaâ€™s score on exam two would fall somewhere between 84 and 88, and only one of our answer choices falls in that range. A good estimate for Sofiaâ€™s score on exam two would be 86.