Introduction
The discipline of psychology makes use of observation methods to come up with concrete description of behavior. Such observations have to occur in a natural setting. Psychological research has four main objectives. These are creating, understanding, prediction and description of change. This process helps psychologists describe the opinions and attitudes of human beings. This helps them predict the mental processes and behavior. Psychologists also try to look at the courses of the behavior. This essay is on an experimental design that tests the effectiveness of a new drug on morbidly obese individuals.
Description of the experimental method
The experimental method for this research is the repeated measures design. In this approach, individuals take part in each step of the experiment more than ones more than one time. Every moment individuals take part in the experimental condition, they accomplish the measure of the dependent variable. This is the reason the experiment is a repeated measures design. In the repeated measures design, all the subjects participate in each stage of the experiment. Repeated measure design utilizes a small number of respondents. This approach is best applicable where we have a few available participants. This measure is more efficient and convenient. This mainly occurs when it takes the participants a short time to complete the experiment (Zechmeister et al, 2001, pp. 156-161).
Repeated experimental designs are highly sensitive in that they can record even small changes in the dependent variables. Errors of variation that result from individual differences are lower in repeated measure designs. The main disadvantage of this design is that individuals may change with time. These experiments require control or else they may result in to confounding (Zechmeister et al, 2001, pp. 156-161).
Justification of the selected method
Repeated measures design is the best approach because all the respondents will take part in all the conditions of the experiment. We do not have different groups of respondents taking part in different conditions of the independent variable. All the morbidly obese individuals who will take part in this experiment will receive a dose of the new drug. Another reason why the repeated measures design is the best approach is that it requires only a few participants. The population of morbidly obese individuals is small and so this approach is the best for this experiment. The final justification for this approach is that the experiment is capable of measuring slight effects in the dependent variable. Any slight changes in the eating habits of the morbidly obese people will course changes in the body weight of morbidly obese people (Zechmeister et al, 2001, p. 156-161).
Identification of the target population
The target population for any experiment should bring out the results of the experiment well. This experiment will target morbidly obese individuals in the society. Morbid obesity is a health condition in which the weight of an individual is two times and above the recommended weight. This condition has close associations with several disorders that are threatening to life. This occurs as a result of taking in a lot of fat. This group is the best target for this experiment because a drop in their appetite will lead to low consumption of food. This will then translate to reduction in body weight.
Description and justification of the sampling plan
The sample in this population will come from the population of morbidly obese individuals the city. The researcher will visit institutions like schools, churches and work places to come up with a sample of obese people. The experimenter will not visit hospitals because this people may be on other medications of obesity. While visiting the social institutions, morbidly obese individuals who are on any form of medication or exercise aimed at cutting on costs will not be part of this study. This is because it can lead to a distortion in findings. 20 percent of individuals in every institution who meet this criterion will take part in this experiment.
Ethical issues for this study
Ethical issues in experimentation are those practices that are morally right. This experiment will ensure that no individual will forcefully participate in the experiment. The experimenter will seek the consent of all the participants. The findings from the experiment will remain confidential from the general public. This is especially because the experiment deals with personal health issues. Unless a participant needs his or her progress to go public, it will remain confidential.
Expectations in results
The performance measure in this experiment is the body weight of the morbidly obese individuals. Because the objective of the experiment is to test whether the new drug can reduce appetite, the experimenter will be expecting a reduction in body weight of the participants. As the individuals keep on taking the new drug, their appetite is should drop. This will reduce the amount of food in take by the individual hence reducing their body weights.
Internal validity threats
Internal validity takes place when the experimenter proofs that the changes in the dependent variable are as a result of the independent variable. In this experiment, the first threat to internal validity is that a reduction in body weight could be as a result of other factors and not the new drug. The morbidly obese participants could be involving in physical exercises at the time of the experiment. Some of them could be having low appetites because of health issues or stress at the time of the experiment. Linking a reduction in body weight to the new drug is not obvious. There could be several factors that lead to a drop in body weight or appetite.
External validity threats
External validity refers to the ability of generalizing findings from an experiment to conditions, settings and individuals outside the scope of the experiment. Morbidly obese individuals have weight problems. This means that they respond faster to the new drug if it is effective in reducing appetite. However, people with normal body weight can take long to respond to such a drug. It becomes challenging to generalize the findings to individuals who are not obese.
Limitations
This experiment handles a highly confidential subject and most of the morbidly obese individuals may not be willing to take part in the experiment. In case the weighing machine experiences technical problems, it can lead to yield wrong results hence resulting in to wrong conclusions. Some participants may withdraw from the experiment if their condition shows no improvement.
Recommendations for future research
There are many morbidly obese people around the world. This condition results in to several health complications that course death. I recommend an extension of this experiment among teenagers. This will assist in controlling obese conditions at earlier ages. I also welcome any improvements on this new drug that reduces appetite.
Conclusion
This paper focuses on the repeated experiment design. It shows how the design is vital in testing a new drug that reduces appetite. This case focuses on morbidly obese individuals. There are recommendations for further research at the end of the experiment.
Reference
Zechmeister, J.S., Zechmeister, E.B., & Shaughnessy, J.J. (2001). Essentials of Research Methods in Psychology. New York: McGraw-Hill.