Concept tests in the screening and evaluation stage of the new-product process rely on written descriptions, sketches, or mock-ups rather than to solicit feedback from potential consumers.

The answer is "Actual products".

Explanation:

The key purpose of this research is to better analyze the concepts, which is done to establish customer buying expectations and perceptions of the item. The key point is to assess the consumers ' initial response to the product idea.

a few, because i should have plenty.