The sample that is chosen in the experiment is important. The participants need to be appropriate for the study and they ideally need to be generalizable to the general public. Sometimes you can only generalize so much and the study will not be generalizable to a wide audience. A random sample should be taken so there is no selection bias. You need to find a large enough sample size in order to make an accurate predictions about the entire population. There should also be random assignment to the experimental group or the control group. This is crucial to make sure that the two groups are roughly equal in all expects except for the independent variable that is being manipulated. In most cases, data is collected from the two groups after selection in order to verify that the groups are equivalent to one another. Failure to do this results in a selection bias. The statistical analysis is when you try to find out if there are any meaningful differences between the two selected groups. Ideally, you will look for a situation where the difference will be detected 95 out of 100 times doing the experiment. This is called the 95 percent confidence limit.
ETHICS IN PSYCHOLOGICAL RESEARCH It is important to make sure that any research that is done meets ethical standards. Modern researchers are well aware of this but it wasn t always the case. Nowadays, there are strict standards and guidelines in place to make sure that the experiment does not cause any harm to the participants. If federal moneys are used for a research experiment, there must be an institutional review board that oversees all research involving human subjects. There needs to be approval from the IRB before the study can proceed. An informed consent needs to be signed by every study participant. In the informed consent, there must be a written description of the proposed study and what the person should expect regarding potential risks. Participants are given the opportunity to back out of the experiment at any time. Confidentiality must be assured and children under 18 years need parental consent in writing. There can be deception in the informed consent if being entirely truthful would skew the results but the deception cannot harm
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