Questions about Quantitative Designs
1.Define external validity and discuss how experimental designs make it difficult to claim. (2 marks)
2.Compare and contrast a non-experimental study design, a pre-experimental study design, and a true experiment. Discuss the three study designs in terms of random assignment to experimental groups and the presence of an intervention or manipulation. (3 marks)
3.Fort Whyte recently started a pre-school program where children aged 3 and 4 engage in typical pre-school programming but, except in the case of extreme weather, spend a minimum of 2 hours outside in a nature setting each day. The people at Fort Whyte who run this program are convinced that having kids outside each day has benefits for children’s learning, attention-span, physical and mental health but they want the data to prove this. They randomly assign students to an intervention or control class. Both classes get the same curriculum but for the experimental class, the manipulation is that students spend 2 hours outdoors. [unique_solution]For the control class, all programming is indoors. At the end of the year, the staff takes outcome measures to examine them for group differences. Two threats related to manipulation could affect the internal validity of the study: Diffusion of treatments and the halo effect. Explain what each of these threats are and how they may threaten internal validity in this particular study. Next, offer at least one way that in which each of these threats could be eliminated, reduced or accounted for. (4 marks)