Amanda is studying relationships between the values and ages of different items. She decides to ask teachers at her school to estimate the values and ages of their cars. She will exclude any antique cars and knows that the value of a car depreciates over time. Which correlation is expected between the age and value of a car?

positive

negative

constant

none

The correct answer is a negative correlation. This means that as one increases, the other decreases. In this case, as the age of a car increases, its value decreases. On a graph this will look like a line going down from the top left to the bottom right. A positive correlation would be the opposite (as one increases, so does the other). A constant correlation means that something is increasing or decreasing at a steady rate (since we don't know how much a car's value depreciates each year, we can't determine if it's a constant relationship).