Types of correlation:
Linear Positive: When the dependient variable increases as the independient variable increases.
Linear Negative: When one variable increases as the other variable decreases.
Non-linear: When the relation is not proportional.
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In this case the variables are:
- How much water the students drink
- GPA
The correlation is a linear negative correlation as when variable "How much water the students drink" increase the varible "GPA" decreases.
If there are no more variables that affect the GPA then, the conclusion of Jose is correct as he can see that the amount of water that the students drink inversely affects the GPA.