Describe the specific attributes of an experimental research design

Describe the specific attributes of an experimental research design.Then, decide whether each of the following topics could be studied using an experimental research design and then explain why or why not. 

    a. Effect of parietal lobe damage on people's ability to do basic arithmetic.

    b. Effect of being clinically depressed on the number of close friendships people have.

  c. Effect of group training on the social skills of teenagers with Asperger's syndrome.

  d. Effect of paying people to take an IQ test on their performance on that test.