Rudy conducts an experiment to test whether excess dietary salt leads to higher blood pressure. His results show that the experimental subjects who had excess salt in their diets had higher blood pressure overall. What should be Rudy's next step?

Rudy's next step must be:

Subject the experimental subjects with high levels of blood pressure identified in the previous step, to a low-salt diet for a certain time, with which once it is finished it can be identified if there was a considerable reduction in the blood pressure of the experimental subjects and directly associate high salt consumption with high blood pressure levels.

Explanation:

High blood pressure levels may be due to inadequate diet, sedentary habits or even family restraints in which multiple members of the same family suffer, so Rudy cannot associate high blood pressure only with the step of increasing levels of salt to some experimental subjects, since the possibility that any other factor is also causing this is open, therefore, she should subject these same experimental subjects to a low salt diet and verify that their blood pressure levels decrease, which could be directly associated with high salt intake with high blood pressure.