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Control GroupsControl groups are an important aspect of true experimental designs. The presence of control groups allows researchers to confirm that study results are due to the manipulation of independent variables (IVs) rather than extraneous variables. Specifically, control groups comprise participants who are not exposed to the manipulated IV but are measured on the study’s dependent variables (DVs). The extent to which an IV is found to cause the DV is calculated by comparing the differences in the DV observed between the control group and one or more experimental groups. It is important to note that control groups are not present in quasi-experimental designs, which instead compare preexisting characteristics within participants and do not involve experimental manipulation of the IV. This entry covers types ... locked icon Sign in to access this contentSign in Get a 30 day FREE TRIAL
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Section 2: Experimental StudiesUnlike a descriptive study, an experiment is a study in which a treatment, procedure, or program is intentionally introduced and a result or outcome is observed. The American Heritage Dictionary of the English Language defines an experiment as "A test under controlled conditions that is made to demonstrate a known truth, to examine the validity of a hypothesis, or to determine the efficacy of something previously untried." This means that no matter who the participant is, he/she has an equal chance of getting into all of the groups or treatments in an experiment. This process helps to ensure that the groups or treatments are similar at the beginning of the study so that there is more confidence that the manipulation (group or treatment) "caused" the outcome. More information about random assignment may be found in section Random assignment. Definition: An experiment is a study in which a treatment, procedure, or program is intentionally introduced and a result or outcome is observed. Case Example for Experimental StudyExperimental Studies — Example 1An investigator wants to evaluate whether a new technique to teach math to elementary school students is more effective than the standard teaching method. Using an experimental design, the investigator divides the class randomly (by chance) into two groups and calls them "Group A" and "Group B." The students cannot choose their own group. The random assignment process results in two groups that should share equal characteristics at the beginning of the experiment. Experimental Studies — Example 2A fitness instructor wants to test the effectiveness of a performance-enhancing herbal supplement on students in her exercise class. To create experimental groups that are similar at the beginning of the study, the students are assigned into two groups at random (they can not choose which group they are in). Students in both groups are given a pill to take every day, but they do not know whether the pill is a placebo (sugar pill) or the herbal supplement. The instructor gives Group A the herbal supplement and Group B receives the placebo (sugar pill). The students' fitness level is compared before and after six weeks of consuming the supplement or the sugar pill. No differences in performance ability were found between the two groups suggesting that the herbal supplement was not effective. What are the principles of experimental research?There are three basic principles behind any experimental design:. Randomisation: the random allocation of treatments to the experimental units. ... . Replication: the repetition of a treatment within an experiment allows: ... . Reduce noise: by controlling as much as possible the conditions in the experiment.. What are some important considerations for experimental research?Look for and eliminate all possible sources of error. Use the highest quality experimental methods, reagents, and instrumentation available. Purify your reagents if you know that they are impure. Collaborate if necessary in order to obtain access to instrumentation and methods that are of the highest quality.
What is the most important purpose of experimental research?What is the Purpose of Experimental Research? Experimental research seeks to determine a relationship between two (2) variables—the dependent variable and the independent variable.
What are the 3 principles used in any experimental design?Three main pillars of experimental design are randomization, replication, and blocking, and we will flesh out their effects on the subsequent analysis as well as their implementation in an experimental design.
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