PSAT Math Multiple-Choice Question 738: Answer and Explanation

Question: 738

If one were to create a graph with age groupings (from younger to older) as the variable along the x-axis and percentage of group members who use video sharing (from smaller to larger) along the y-axis, what would be the relationship portrayed by the data?

• A. Positive correlation
• B. Negative correlation
• C. Equivalence
• D. Exponentially inverse

Correct Answer: B

Explanation:

(B) As the age groups gradually increase in value (from 12 through 61+), the number of group members using video sharing steadily decreases (from 40 to 2). A negative correlation is defined as the relationship between two variables such that when one variable increases, the other variable decreases. So the relationship between age groups and percentage of group members using video sharing can best be described as a negative correlation. A positive correlation is when the variables increase with one another. Equivalence simply means the variables are equal. An exponentially inverse relationship means that as one variable increases, the other decreases at an exponential rate. The decrease in video sharing is relatively steady, so the terms cannot be described as having an exponentially inverse relationship.