In a pharmacological experiment on eating behavior in rats, 18 rats are to be ra
ID: 3181588 • Letter: I
Question
In a pharmacological experiment on eating behavior in rats, 18 rats are to be randomly allocated to three treatment groups: T1, T2 and T3. While under observation, the animals will be kept in individual cages in a rack. The rack has three tiers with six cages per tier. In spite of efforts to keep the lighting uniform, the lighting conditions vary somewhat from one tier to another (the bottom tier is darkest), and the experimenter is concerned about this because lighting is thought to influence eating behavior in rats. The following three plans are proposed for allocating the rats to positions in the rack: Plan I - Randomly assign the 18 rats to the 18 positions in the rack. Plan II - Put all T1 rats on the first tier, all T2 rats on the second and all T3 rats on the third tier. Plan III - On each tier, put two T1 rats, two T2 rats and two T3 rats. Which of the plans has a problem with confounding? A. Plan III B. Plan I C. Plan II D. None of the aboveExplanation / Answer
The answer ic C. Plan II. Plan II would be having a problem with confounding. Each tier has a different level of lighting conditions which would act as a confounding variable and affect the eating behavior of rats. So if different treatments are given to each tier and each tier has also different lighting conditions , it would be not possible to determine the effect of different treatments on eating behavior of rats (as it may be affected by the confounding variable, lighting conditions).
For other plans, since different treatments are assigned to different tiers, the effect of the confounding variable would be minmized.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.