Answer:
- Response variable: The amount of vision the patients obtained after surgery.
- Explanatory variable: The type of detached retina surgery carried out.
Explanation:
Response variable is the main focus of a question when carrying out a study or experiment. Whereas, an explanatory variable is the variable one that explains the changes in the response variable.
Now, in the question we are given it is clear that the main focus of the study is to determine if patients were able to regain vision.
Thus, the response variable is; the amount of vision the patients obtained after surgery.
Now, what determines if patients were able to regain vision is hinged on the 2 retina surgeries which are: laser surgery and freezing treatment.
Thus, the explanatory variable is; The type of detached retina surgery.