A testable question is the one which can be answered using experiment and research. A non-testable question is the one which cannot be answered using experimental trials.
Example:
Non-testable: Which is more better ice-cream or chips?
Testable: Which is more better nutritionally ice-cream or chips?
Here, in the non-testable question no parameter was given for comparision and analysis hence, it cannot be tested experimentally. Whereas, in the testable question nutritional quality is to be compared between the two food items.
