Which of the following relationships represents a positive correlation between two variables?
A.
As a student’s class attendance decreases, the student’s overall grade remains the same
B.
As the number of hours a person exercises decreases, the weight of that person increases
C.
As the number of miles driven increases, the amount of the gasoline in the tank decreases
D.
As the amount of water plant receives increases, the growth rate of the plant increase.
The correct answer and Explanation is :
The correct answer is D. As the amount of water a plant receives increases, the growth rate of the plant increases.
Explanation:
A positive correlation occurs when two variables move in the same direction. In other words, as one variable increases, the other variable also increases. Similarly, if one decreases, the other decreases. The closer the relationship between the variables, the stronger the correlation.
Let’s review each option:
- Option A: “As a student’s class attendance decreases, the student’s overall grade remains the same.”
This is not a correlation. The student’s grade stays constant regardless of changes in attendance, meaning there is no relationship between the two variables. - Option B: “As the number of hours a person exercises decreases, the weight of that person increases.”
This represents a negative correlation, where one variable (exercise) decreases while the other (weight) increases. In a negative correlation, the variables move in opposite directions. - Option C: “As the number of miles driven increases, the amount of gasoline in the tank decreases.”
This is also a negative correlation. As the distance driven (miles) increases, the gasoline decreases, indicating that they move in opposite directions. - Option D: “As the amount of water a plant receives increases, the growth rate of the plant increases.”
This is a positive correlation. Both variables—amount of water and plant growth—move in the same direction. When a plant receives more water, it typically grows at a faster rate. In contrast, if the plant receives less water, its growth would slow down, demonstrating the direct relationship between the two variables.
Thus, Option D correctly represents a positive correlation where the increase in one variable leads to an increase in the other.