Randomized experiments are experimental designs that involve ...

[plus1]

Randomized experiments are experimental designs that involve
 
  a. the manipulation of variables.
  b. the use of humans as research participants.
  c. the use of random assignment to treatment conditions.
  d. the strict adherence to ethical guidelines.

Question 2

When one's research purpose is to make causal generalizations, one must be concerned with the __________ validity of how the variables are conceptualized.
 
  a. face
  b. construct
  c. internal
  d. content

[Chou]

Answer to Question 1

c

Answer to Question 2

b