Describe the major difference between quasi experimental and true experimental design. In other words, what criterion separates the two?

Describe the major difference between quasi experimental and true experimental design. In other words, what criterion separates the two? (2 points)

 

 

 

 

  1. Briefly describe single blinding versus double blinding. Why is blinding a valuable tool when conducting a clinical trial? (3 points)

 

 

 

  1. Contrast internal vs external validity of a study. (2 points)

 

 

  1. A researcher wishes to conduct an experiment in which he wishes to measure the efficacy of a nutritional protocol for lowering LDL levels. His budget allows him to only assemble and study two groups.
  2. What would be the best study design based on this constraint? (1 point)

 

 

  1. Suppose 5 individuals cannot tolerate the study and drop out. What is the term given to subjects dropping out? Suggest a way in which this might threaten the validity of the study. (2 points)

 

 

 

  1. Please consider the following link to assist you in answering question 4:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2917255/

Researchers interview the parents of children diagnosed with a hyperactivity disorder for the potential efficacy of a nutrition intervention.  Following unfavorable results to the study, the researchers (as well as their trial sponsors) decide not to publish.  What is the most likely type of bias introduced in the above scenario? (1 point)

 

 

 

 

  1. Contrast unsystematic (random) vs systematic variability. How are they different? (2 points)

 

 

 

 

  1. Describe two types of bias that may present in research. You may use the link from question 4, but do not use the same example. Then, describe how one would control or minimize these two types of biases. (4 points)

 

 

  1. Please refer to the following study for question 7.

Kroke, A, et al. Validation of a self-administered food-frequency questionnaire administered in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study: comparison of energy, protein, and macronutrient intakes estimated with the doubly labeled water, urinary nitrogen, and repeated 24-h dietary recall methods. The American journal of clinical nutrition 1999; 70(4): 439-447.

 

You can find the study here:

https://ajcn.nutrition.org/content/70/4/439.full

 

  1. What specific study design was employed? (1 point)

 

  1. Please read the three paragraphs of the Introduction. In your own words, describe the type of bias that the author introduces. Be as specific as possible. (1 point)

 

 

b. With regards to this study, how does self-reporting of energy intake using questionnaires correlate with the validated biomarker methods used in the study.  You do not need to cite specific data, but rather summarize the studies’ findings.