Answer to Question 1
C
Feedback:
Quasi-experiments involve an intervention but lack randomization and sometimes even a comparison group. Strong quasi-experimental designs introduce controls to compensate for these missing components. In crossover designs, people are exposed to more than one experimental condition in random order and serve as their own controls. Experiments involve an intervention; control; and randomization or random assignment. Retrospective designs involve collecting data about an outcome in the present and then looking back in time for possible causes.
Answer to Question 2
B
Feedback:
Quasi-experiments (trials without randomization) involve an intervention but lack randomization and, sometimes, a control group. Strong quasi-experimental designs introduce controls to compensate for these missing components. Matching of subjects is a method of controlling confounding variables by consciously forming comparable groups, which is used in some, but not all, quasi-experiments.
Example of pre- and posttest Interpretation in an Experiment
Group Performance
Group defenses: Cluster of sawfly caterpillars regurgitating fluid (yellow) that predators find unap
Self-splicing of group I introns
The consequences of crossover in the inversion loop in paracentric inversion heterozygotes