The height of the water in a reservoir increases as the number of inches of rain per hour increases.
B
The number of pets does not have a connection with the amount of food a person eats.
C
The tree needs more nutrients as it grows.
D
As a hike progresses, hikers tend to drink more water.
A
Positive association
B
No association
C
Positive association
D
Negative association
Practice makes perfect
We want to find the association between the number of inches of rain per hour and the height of the water in a reservoir. Let's consider the most common types of association.
Observation
Type of Association
As one variable increases, the other variable increases.
Positive
As one variable increases, the other variable decreases.
Negative
There is no visible pattern.
None
The height of the water in a reservoir increases when there is more rain. This means that the height of the water in a reservoir increases as the number of inches of rain per hour increases. This is a positive association.
Let's consider the next statement.
The amount of food a person eats and how many pets he or she has.
Imagine that a person already has two pets. Even if they get a third pet, the person will still eat the same amount of food per day. The number of pets does not have a connection with the amount of food a person eats. This means that there is no association.
Let's consider the third statement.
The height of a tree and the amount of nutrients it gets.
The tree needs more nutrients as it grows. This means that as the height of the tree increases, the amount of nutrients the tree gets increases. Therefore, the association is positive.
Let's consider the final statement.
The number of hours spent hiking in the mountains and the amount of water left in your water bottle.
When we go on a hike, we need to drink water. As time passes and we spend more hours hiking, the amount of water in our bottle decreases because we drink the water. This is a negative correlation.
