Using the attached article, diagram the experiment using the exhibits in chapter 6 as a model. Discuss the extent to which experimental conditions were controlled and the causal mechanism was identified. Based on a review of the threats to internal validity —selection bias, endogenous change, external events, contamination, and treatment misidentification—how confident can you be in the causal conclusions from the study? How generalizable do you think the study’s results are to the population from which the cases were selected? How generalizable are they to specific subgroups in the study? How thoroughly do the researchers discuss these issues?
