Example 1.21 from Statistics, 1.4 Experimental Design and Ethics

Experimental Design and Ethics: example 1.21

The Smell & Taste Treatment and Research Foundation conducted a study to investigate whether smell can affect learning. Subjects completed mazes multiple times while wearing masks. They completed the pencil and paper mazes three times wearing floral-scented masks, and three times with unscented masks. Participants were assigned at random to wear the floral mask during the first three trials or during the last three trials. For each trial, researchers recorded the time it took to complete the maze and the subject’s impression of the mask’s scent: positive, negative, or neutral.

Describe the explanatory and response variables in this study.
What are the treatments?
Identify any lurking variables that could interfere with this study.
Is it possible to use blinding in this study?

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

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Solution
1. The explanatory variable is scent, and the response variable is the time it takes to complete the maze.
2. There are two treatments: a floral-scented mask and an unscented mask.
3. All subjects experienced both treatments. The order of treatments was randomly assigned so there were no differences between the treatment groups. Random assignment eliminates the problem of lurking variables.
4. Subjects will clearly know whether they can smell flowers or not, so subjects cannot be blinded in this study. Researchers timing the mazes can be blinded, though. The researcher who is observing a subject will not know which mask is being worn.

How did it go?

Solution

Solution