A research study is described below Critique this study in t

A research study is described below. Critique this study in terms of control, randomization, and replication. It is estimated that about 100 words are necessary for a complete response.

A group of culinary arts students conducted a research study to explore the impact of vision on food preferences. Their sample consisted of 18 students in an introductory cooking class. Each participant signed up for one data collection session. There was a morning session, (8-9AM) and an evening session (8-9PM). An equal number of participants signed up for each session. Both sessions received the same food. For the morning sessions, participants were blindfolded so they couldn’t see what they were being served. For the evening session participants were not blindfolded and could see what they were being served. Participants rated the taste of the food. The morning session gave higher ratings for taste, so the researchers concluded that being blindfolded makes food taste better.

Solution

The problem with this experiment is that the reasearcher has neglected to control for the effect of the differences in the viewing of food. This leads to experimental bias, the favoring of certain outcomes over others. To avoid this bias, the researcher should have tested the food in identical conditions to the control group. Without controlling for outside variables, the researcher cannot conclude that it was the effect of the blindfold, and not the view, that produced a better rating of morning session.

Because it is generally extremely difficult for researchers to eliminate bias using only their expert judgment, the use of randomization in experiments is common practice. In a randomized experimental design, objects or individuals are randomly assigned (by chance) to an experimental group. Using randomization is the most reliable method of creating homogeneous treatment groups, without involving any potential biases or judgments. There are several variations of randomized experimental designs. In this experiment the researcher should have randomized the partcipants for the two sessions. This might have been a Completely Randomized Design or Randomized Block Design.

Although randomization helps to insure that treatment groups are as similar as possible, the results of a single experiment, applied to a small number of objects or subjects, should not be accepted without question. Randomly selecting two individuals from a group of four and applying a treatment with \"great success\" generally will not impress the public or convince anyone of the effectiveness of the treatment. To improve the significance of an experimental result, replication, the repetition of an experiment on a large group of subjects, is required. If a treatment is truly effective, the long-term averaging effect of replication will reflect its experimental worth. If it is not effective, then the few members of the experimental population who may have reacted to the treatment will be negated by the large numbers of subjects who were unaffected by it. Replication reduces variability in experimental results, increasing their significance and the confidence level with which a researcher can draw conclusions about an experimental factor. So, dfferent replications must have been tried before coming to conclusion.