advantages of experiment: (4)-disadvantages of experiment: (4) -conducting an ex
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Question
advantages of experiment: (4)-disadvantages of experiment:
(4) -conducting an experiment needs a series of activities to carry it out successfully. Researcher should do activities to accomplish to make it successful. (7 activities), Name and explain.
-threats to internal validity of experiment (7 threats), name and explain.
-threats to external validity of experiment (3 threats) name and explain.
-experimental research design (3) name and explain.
-true experimental design (4) name and explain.
Explanation / Answer
Ans 1.
Advantages of Experiments:
1. A High Level of Control Over Variables
The people conducting an experiment have a high level of control over their variables. The purpose of control is to enable the experimenter to isolate the one key variable which has been selected (called as independent variable) in order to observe its effects on some other variable(the dependent variable); this control is to conclude that it is only the independent, and nothing else, which is influencing the dependent variable.
2. Cause and Effects
Experiments are the only means by which cause and effects can be established because it involves deliberate manipulation of one variable while trying to keep all other variable constant. Sometimes the independent variable is thought of as the cause and dependent variable as the effect. Thus, an experiment differs from non-experimental methods in that it enables us to study the cause and effects.
3. Validity of the Theory by Replication of Experiments
Experiments can be replicated. We cannot generalise from the results of a single experiment. The more often an experiment is repeated, with the same results obtained, the more confident we can be that the theory being tested is valid. The experimental methods consists of standardised procedures and measures which allow it to be easily repeated.
4. Validity of data
An experiment yields quantitative data (numerical amounts of something) which can be analysed using inferential statistical tests. These tests permit statements to be made about how likely the results are to be have occured through chance.
Ans 2.
Disadvantages of Experiments:
1. Artificiality
Most experiments are conducted in labs - strange and contrived environments in which people are asked to perform unusual or even bizzare tasks. The artificiality of the lab, together with the unnatural thing that the subjects may be asked to do, jointly produces a distortion of behaviour. Therefore it should be difficult to generalise findings from the experiments becayse they are not ecologically valid (true to real life).
2. Behaviour
Behavour in the lab is very known to its range. By controlling the situation so precisely, behaviour may be limited.
3. Demand Charactersticks.
A major difficulty with the experimental method is demand characterstics. Some of many confounding variables in psychology experiment stem from the fact that a psychology experiment is a social situation in which neither the Subject or the Experimenters are passive, inanimate objects but are active, thinking humans. Demand characterstics are all the cues which convey to the participant the purpose of the experiment.
4. No Complete Control
It has already been explained that a strength of the experimental method is the amount of control which the experimenters have over the variables. However it must also be noted that it not possible to completely control all variables. There may be other variables at work which the experimenter is unaware of. In particular, it is impossible to completely control the mental world of people taking part in a study.
Ans 3.
Activities done to carry out an experiment successfully:
1. Scoping
The hypothesis has to be stated clearly. Furthermore, the objective and goals of the experiments must be defined. The goal is formulated from the problem to be solved.
2. Find the Best Method to Get the Job Done
With so many protocols out there, it can be overwhelming to try and narrow it down to just one. After taking into account the cost of the reagents, whether someone you know has done it before, and how widely the technique has been used, in the end, you just have to pick one and go with it!
3. Planning
The planning activity is where the foundation for the experiment is laid. The context of the experint is deternined in detail. This includes personnel and the environment, for example, whether the experiment is run in a university environment with students or in an industrial setting. Moreover, the hypothesis of the experiment is stated formally, including a null hypothesis and an alternative hypothesis.
Planning involves choosing a suitable experiment design, determining variables (both independent and independent) and instrumentation.
The planning is crucial step in an experiment to ensure that the result from the experiment becomes useful. Poor planning may ruin any well intended study.
4. Prepare a timeline
Try to realistically estimate how long each procedure will take, and if you are not sure, double the time that you think it will take. Don't try to cram too much into one day - you are more likely to make errors when you are rushing.
5. Operations
The operations consists in principle of three steps: preparation, execution and data validation. In the preparation step, we are concerned with preparing the subjects as well as the material needed, for example, data collection forms. The participants must be informed about the intention; we must have their consents and they must be commited. The actual execution is nomally not a major problem. The main concern is to ensure that the experiment is conducted according to the plan and design of the experiment, which includes data collection. Finally, we try to make sure that the actually collected data is correct and provide a valid picure of the experiment.
6. Analysis and Interpretation
The data collected during the operetion provide the input to this activity. The data can now be analyzed and interpreted. The first step in the analysis is to try to understand the data by using descriptive statistics. The next step is to consider whether the data set should be reduced, either by removing data points or by reducing the number of variables ny studying if some of the variables provide same or irrelevant information. After having removed data points or data sets, we are able to perform hypothesis test, where the actual test is chosen based on measurement scales, values on the input data and the type of results we are looking for. One important aspect of this activity is the interpretation. That is, we have to determine from the analysis whether the hypothesis was possible to reject.
7. Presentation and package
The last activity is concerned with presenting and packaging of the findings. This includes primarily documentation of the results, which can be made either through a research paper for publication, a lab package for replication purposes or as part of a company’s experience base. This last activity is important to make sure that the lessons learned are taken care of in an appropriate way. Moreover, an experiment will never provide the final answer to a question, and hence it is important to facilitate replication of the experiment.A comprehensive and
thorough documentation is a prerequisite to achieve this objective.
Ans 4.
Threats to Internal Validity
1. Ambiguous Temporal Precedence
Lack of clarity about which variable occurred first may yield confusion about which variable is the cause and which is the effect.
2. Confounding
A confounder is a variable that is correlated either directly or indirectly to both dependent and independent variable. A major threat to the validity of casual inferences is confounding. Changes in the dependent varaible may rather be attributed to the existence or variaions in the degree of a third variable which is related to the manipulation variable.
3. Selection Bias
Selection bias refers to the problem that, at pre-test, differences between groups exist that may interact with the independent variable and thus be responsible for the observed outcome. Researchers and participants bring the experiment a myriad of characterstics, some learned and others inherit.
During the selection step of the research study, if an unequal number of test subjects have similar subject-related variables there is a threat to the internal validity.
4. History
Participants' responses to experimental procedures may be effected by the events outside of the study/expriment or between repeated measures of the dependent variables. Often, these are large scale events (natural disaster, political change, etc.) that affect participants' attitudes and behaviors such that it becomes impossible to determine whether any change on the dependent measures is due to the independent variable, or the historical event.
5. Maturation
Subjects change during the course of the experiment or even between measurements. Both permanent changes, such as physical growtrh and temporary ones like fatigue, provide natural alternative explanations; thus they may change the way a subject would react to the independent variable.
6. Testing Effects
Repeatedly measuring the participants may lead to bias. Participants may remember the correct answers or may be conditioned to know that they are being tested. Repeatedly taking the (Same or similar) intelligence tests usually lead to score grains.
7. Instrumental Change
The instuments used during the testing process can change the experiment. If any instrumentation changes occur, the internal validity of the main conclusion is affected, as alternative explanations are readily available.
Ans 5.
Threats to External Validity
A thread to external validity is an explanation of how you might be wrong in making a generalization.
1. Aptitude–treatment Interaction: The sample may have certain features that may interact with the independent variable, limiting generalizability.
2. Situation: Situational specifics such as treatment conditions, time, location, lighting, noise etc., of a study potentially limit generalizability.
3. Reactive effects of experimental arrangements: An experiment in remedial reading instruction has an
effect that does not occur when the remedial reading program, which is the experimental treatment, is
implemented in the regular program.
Hope this helps...
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