Imagine you wanted to design a quasi-experiment to study the hypothesis that delaying the start of the day in high schools to 8:30 a.m. or later causes teens to suffer less depression. Imagine that there are four public high schools, all in the same area of the country, that are willing to participate in this study. Currently, they all start between 7:20 a.m. and 7:35 a.m., but in fact, two of the high schools are already planning to change their starting times next fall.

1. Why might it be more practical to conduct a quasi-experiment on this question, rather than a true experiment?

2. Design four studies

• • Nonequivalent control group design (posttest-only)
  • Nonequivalent control group design (pretest/posttest).
  • Interrupted time-series design
  • Nonequivalent control group interrupted time-series design

3. Explain how you would design each study. Explain whether or not each study can support the causal statement.