Answer: This scenario demonstrates "COVARIATION BETWEEN VARIABLES".
Explanation: Covariation between variables is how two variables are interrelated. It shows if two variables are inversely or directly proportional.
Non-experimental research only show how two variables are interrelated, which means that Covariation between variables describes non-experimental research. In an non-experimental research, the research does not accurately determine cause, rather it projects the relationship between the choose variables.
In this research, the researcher collected data on exercise and anxiety, this means the researcher wants to correlate the two variables.