8.9 Exercises

Selected answers are available in Sect. D.8.

Exercise 8.1 Consider this RQ (based on Teillet et al. (2010)):

Among university students, is the taste of tap water different than the taste of bottled water?

You want to answer this question using an observational study. Describe what these might look like for this study:

  1. Random allocation.
  2. Blinding.
  3. Double blinding.
  4. Control.
  5. Finding a random sample.
Exercise 8.2 Is it possible to have a control group in an observational study? Explain.
Exercise 8.3 Is the Hawthorne effect only a (potential) issue in experimental studies? Explain.

Exercise 8.4 A study of how well hospital patients sleep at night (Delaney et al. 2018) had the stated aim ‘to investigate the perceived duration and quality of patient sleep […] in hospital.’ In discussing the limitations of the study, the researchers state:

The researchers made no attempt to deceive clinical staff regarding the nature of the study so the influence of the Hawthorne Effect should be considered. The presence of the observer and environmental monitoring equipment in the clinical environment could have altered behaviour among patients and nursing staff seeking to conform to the presumed research objectives. As a result, the findings reported may be an underestimation of the magnitude of the issues that affect sleep.

— (Delaney et al. (2018) p. 7)

Discuss these limitations in terms of the language used in this chapter.


Delaney LJ, Currie MJ, Huang H-CC, Lopez V, Van Haren F. “They can rest at home”: An observational study of patients’ quality of sleep in an Australian hospital. BMC Health Services Research. BioMed Central; 2018;18(1):524.
Teillet E, Urbano C, Cordelle S, Schlich P. Consumer perception and preference of bottled and tap water. Journal of sensory studies. Wiley Online Library; 2010;25(3):463–80.