For each of the following studies, state (1) whether random selection was likely to have been used, and explain whether it would have been possible to use it. Also, describe the population to which the researcher wanted to and could generalize, and state (2) whether random assignment was likely to have been used, and whether it would have been possible to use it. 

a. A developmental psychologist wondered whether children born preterm (prematurely) had different social skills at age 5 than children born at full term. 

b. A counseling center director wanted to compare the length of therapy in weeks for students who came in for treatment for depression versus students who came in for treatment for anxiety. She wanted to report these data to the university administrators to help develop the next year’s budget. 

c. An industrial-organizational psychologist wondered whether a new laptop design would affect people’s response time when using the computer. He wanted to compare response times when using the new laptop with response times when using two standard versions of laptops, a Mac and a PC.