Some researchers have noted that adolescents who spend a lot of time playing video or computer games are at greater risk for depression and for violence. This is an example of A. a valid conclusion since more time yields more aggression is a positive association. B. an observational study with lurking variables that may explain the association. C. a single-blind experiment because the subjects knew they were watching television. D. a paired data experiment since we are studying both aggression and TV watching. Solution B. an observational study with lurking variables that may explain the association. Option - B as the study is observational with some parameters used to calculate the association.