Dr rodriguez is interested in finding out if stress levels throughout the year have a relationship with students grades. The resseaarch method she most likely used is

Dr. Rodriguez most likely used a correlational research method.

Correlation Study

Explanation:

Correlation Study -

It refers to the type of study, used in the field of psychology.

In this type of study, the information or data is collected manually, rather than considering any type of experiment, is referred to as correlation study.

In this study, the relation between the two or more data is considered in this method.

Hence, from the given scenario of the question,

The correct answer is correlation study.