Question

lizs math test included a survey question asking how many hours students spent studying for the test. the scatter plot and trend line plots the relationship between how many hours students spent studying and their score on the test. assuming the line is correct, what does the lines slope of 15 mean?
choose 1 answer:
on average, students who didnt study at all got scores of about 15 on the test.
if one student studied for one hour more than another student, the student who studied more got exactly 15 more points on the test.
on average, studying for one extra hour was associated with a 15 point improvement in test score.
on average, studying for 15 extra hours was associated with a 1 point improvement in test score.

Explanation:

• Option A: The y - intercept (not the slope) represents the score when study time is 0. So A is incorrect.
• Option B: The slope shows a trend or average, not that every student who studies one more hour gets exactly 15 more points. So B is incorrect.
• Option C: The slope of a line in a scatter plot (trend line) represents the average rate of change. Here, a slope of 15 means that for each additional hour of study (increase in x - value by 1), the test score (y - value) increases by 15 on average. This matches the interpretation of slope as the average change in y per unit change in x.
• Option D: A slope of 15 means 15 - point change per hour, not 1 - point change per 15 hours. So D is incorrect.

Answer:

C. On average, studying for one extra hour was associated with a 15 point improvement in test score.