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Logic of experimental designs
Ethical concerns in an experimental study
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Recommended: Logic of experimental designs
Introduction
“Maximin design maximizes either the minimum efficiency, or the minimum relative efficiency of the design relative to the optimal design, over a range of plausible parameter values, by choosing the design with the highest minimum” (van Breukelen, 2013, p. 154).
A project worthy of research requires a logical design with strongly articulated elements, appropriate representative populations, and implemented controls to produce conclusive results to support theories, hypothesis, and the proposed research questions. Components of a research study can make a perfectly design research project fail based on validity, confounds, and faulty causal-relationships conveyed as proper correlations. These aspects are at the root of debates on the legitimacy of qualitative research and the coherence of logic in standard research designs (Maxwell, 1992; 1998).
In this paper, the discussions focus on the purpose, advantages, and disadvantages of conducting experimental designs, importance of internal and external validity claims, define what is/are control, control groups, confound, cause, and how correlation and causation are related. Finally, concluding with specific questions identified for this assignment.
Purpose of conducting an experiment
Researcher use experiments to predict whether a cause and effect relationships exist between variables of interests in cognation of discovering new, or confirming established phenomena, and communicating such knowledge of experimental work for acceptance by the relative community (Hart, Mulhall, Berry, Loughran, & Gunstone, 2000; Jackson, 2012). Experimental designs support a unique distinctions based the designs efficiencies to manipulate control over variables of interest and predict a...
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...SAGE Publications, Inc. doi: http://dx.doi.org.proxy1.ncu.edu/10.4135/9781412961288.n77
Roe, B. E., & Just, D. R. (2009). Internal and external validity in economics research:
Tradeoffs between experiments, field experiments, natural experiments, and field data. American Journal of Agricultural Economics, 91(5), 1266-1271. doi:10.1111/j.1467-8276.2009.01295.x
Teunissen, C., Menge, T., Altintas, A., Alvarez-Cermeño, J., Bertolotto, A., Berven, F., &...
Bartos, A. (2013). Consensus definitions and application guidelines for control groups in cerebrospinal fluid biomarker studies in multiple sclerosis. Multiple Sclerosis (Basingstoke, England), 19(13), 1802-1809. doi:10.1177/1352458513488232 van Breukelen, G. P. (2013). Optimal experimental design with nesting of persons in organizations. Zeitschrift Für Psychologie, 221(3), 145-159. doi:10.1027/2151-2604/a000143
Multiple sclerosis (MS) is a disease affecting the myelination of the central nervous system, leading to numerous issues regarding muscle strength, coordination, balance, sensation, vision, and even some cognitive defects. Unfortunately, the etiology of MS is not known, however, it is generally thought of and accepted as being an autoimmune disorder inside of the central nervous system (Rietberg, et al. 2004). According to a study (Noonan, et al. 2010) on the prevalence of MS, the disease affects more than 1 million people across the world, and approximately 85% of those that are affected will suffer from unpredictably occurring sessions of exacerbations and remissions. The report (Noonan, et al. 2010) found that the prevalence of MS was much higher in women than in men, and that it was also higher in non-Hispanic whites than in other racial or ethnic groups throughout the 3 regions of the United States that were studied.
If a study is confounded, the researcher is not absolutely certain that changes in the dependent variable were caused by the manipulation of the independent variable, or some other uncontrolled variable. In a non-equivalent control group post-test only design, any differences observed between the two classes may be due to the non-equivalence of the groups and not to the injection of quizzes. No pre-test measures were given to establish equivalence.
Going into details of the article, I realized that the necessary information needed to evaluate the experimental procedures were not included. However, when conducting an experiment, the independent and dependent variable are to be studied before giving a final conclusion.
Experimental research is the one type of research that allows psychologists to make causal statements. It is where the researcher changes one or more variables that may have an effect on some other variables (King, 2016). The hypothesis is a specific expectation about what is going to happen in the experiment (King, 2016). In the research, the hypothesis was that women would perceive fat talk to be more socially acceptable than men (Katrevich et al., 2014). The other elements of experimental method are dependent and independent variables. The independent variable (IV) is the cause of the results, and it is changed by the experimenter to find the effects, but the dependent vari...
Wiley Online Library, 2013. The Epidemiology of Multiple Sclerosis [online] Available at: <. http://onlinelibrary.wiley.com/doi/10.1111/j.1600-0404.1997.tb08143.x/abstract> [Accessed 05 December 2013].
Multiple Sclerosis has been categorized into four different subtypes according to the distinct neuropathological changes accompanying the disease (Antony, DesLauriers, Bhat, Ellestad & Power, 2011).
In order to have a successful, reliable experiment you need sufficient data and evidence, reliable research, variables to test and a follow – up experiment. There are several types of variables you need to do an experiment. An independent variable is the manipulated experimental factor that is changed to see what the effects are. A dependent variable is the outcome. This factor can change in an experiment in reaction to the changes in the independent variable. An experimental group is the group of participants that are exposed to the change that the independent variable represents. The control group is participants who are treated in the same way as the experimental group except for the manipulated factor which is the independent variable (King 24). Proper data, evidence and research is also needed so the experiment turns out correctly and you know what you are testing. A follow – up experiment is not required, however it helps the validity of the conclusion of the experiment. Validity is “the soundness of the conclusions that a researcher draws from an experiment” (King 25). Conducting a follow – up experiment will help researchers and people alike see if the experiment worked properly, continues to help people and see how participants are doing after the experiment is over.
Multiple Sclerosis (MS) is a complicated chronic deteriorating disease that has an effect on the central nervous system (CNS). This disease causes destruction of the myelin around the nerve fibers. “The exact etiology of Multiple Sclerosis is unknown; however, it is thought to be an immune mediated disease. MS is characterized by CNS inflammation, demyelination, and axonal loss” (Compston & Coles, 2008). Typically, it is described by early relapses and remissions of neurological signs of the CNS. This is known as relapsing-remitting MS (RRMS). MS can be identified by a variety of known risk factors. Multiple Sclerosis can be brought on by a mixture of inherited and environmental risk factors such as smoking or an exposure to a virus like Epstein Barr. The inflammatory process has an interesting role on the central nervous system.
The design for this study will be a simple between subject experiment consisting of one experimental group and one control group. The independent variable will be warm colors. The dependent variable will be mood. The main goal is to determine if the independent variable will influence or cause difference in the specified dependent variable. The experiment group will spend 60 minutes in a warm paint color room and their mood will be measured. The control group will spend 60 minutes in a neutral paint color room and their mood will be measured.
A researcher uses an experiment to scientifically test out a hypothesis. In an experiment there are many different factors that are involved. There is the independent variable, which is the cause, it is the one that is being manipulated, and the dependent variable, which is the effect, is the response. When conducting a experiment it is important to make sure that the only thing than can affect the dependent variable is the independent variable. This is known as internal validity. Using random assignment to separate the participants into groups helps eliminate any outside factors, and creates an equal chance for all participants to be apart of the experimental conditions. There are many pros and cons to this type of method. The experimental method creates a strong control of the variables involved in the experiment, which allows an easier determination on cause and effect. If needed, it is fairly easy to replicate an experiment and is less time consuming than other research methods. However there are many downfalls as well. When conducting an experiment the setting of where the experiment is taking place is more artificial which may cause certain behaviors that wouldn’t occur in real life. This is known as external validity, which is the measure of how much the results of a study can be generalized and used in different situations, and people. To improve external validity cover stories are created when conducting experiments so the participants are not aware of what is really going on, or experiments are done in a natural setting as opposed to in a laboratory. However, this creates less control over confounding variables that can affect the experiment, which can create bias results (Aronson,
Creswell, J. W. (2009). Research design: Qualitative, quantitative, and mixed methods approaches (3rd ed.). Thousand Oaks, CA: Sage Publications.
Maxwell’s research design has a definite structure. At the center of the design study, research questions should have a clear relationship to the goals or issues you want to address and why. Subsequently, the goals of the research should reflect previous knowledge, current theories and concepts and how they relate to the subject. However, if the research methods do not allow you to answer your research questions and/or validate them, your design will be
Marshall, C, Rossman, Gretchen B, (2006). Designing qualitative research, 4th edition, Thousand Oaks, California: Sage Publications.
The first method to be discussed and analysed are experimental methods. There is a variety of experimental methods including; laboratory, field and natural experiments. These methods are the most scientific method due to them being highly objective and systematic. In addition, this method is regarded as the most powerful research method used in psychology because of the potential to investigate the causes of events and therefore, identifying the cause and effect relationship. When carrying out an experiment the researcher intervenes directly in the situation being investigated. The researcher manipulates an independent variable (IV) in order to investigate whether there is a change in the dependent variable (DV). Any other variables that could have an
A two-phase sequential explanatory strategy was used for the study. The two- phases are ordered in the sequence that was proposed as priority was placed on quantitative data collection and analysis. In the second phase, qualitative data was collected and used to refine the results of the quantitative data presented in the first phase.