A graph shows average annual rainfall and a plant growth rate. If rainfall increases and plant growth rate also increases, what can you infer?

• A. Negative correlation
• B. Positive correlation
• C. No correlation
• D. Random relationship

Answer: (B)

Two variables being looked at are rainfall and plant growth. When both rise together, that indicates a positive correlation—their increases are associated with each other. If the graph shows that as rainfall goes up, plant growth rate also goes up, it demonstrates this positive relationship. This differs from a negative correlation (one goes up while the other goes down), no correlation (no clear pattern), or a random relationship (unpredictable). Keep in mind that correlation doesn’t prove that rainfall causes the growth increase, but the upward trend on the graph shows a positive association between the two.