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A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable (i.e. confounding variables). [1] This increases the reliability of the results, often through a comparison between control measurements and the other measurements. Scientific controls are a part of the ...
A negative control is known to give a negative result. The positive control confirms that the basic conditions of the experiment were able to produce a positive result, even if none of the actual experimental samples produce a positive result. The negative control demonstrates the base-line result obtained when a test does not produce a ...
Population control is the practice of artificially maintaining the size of any population. It simply refers to the act of limiting the size of an animal population so that it remains manageable, as opposed to the act of protecting a species from excessive rates of extinction , which is referred to as conservation biology .
In negative frequency-dependent selection, the fitness of a phenotype or genotype decreases as it becomes more common. This is an example of balancing selection . More generally, frequency-dependent selection includes when biological interactions make an individual's fitness depend on the frequencies of other phenotypes or genotypes in the ...
Also, the percent of unsatisfactory marks in the experimental group was 1.7 times less than in the control group. From this data, Shcherbatykh concluded that the application of self-regulating actions before examinations helps to significantly reduce levels of emotional strain, which can help lead to better performance results.
In the 1960s, Walter Mischel tested four-year-old children for self-control via the "marshmallow test": the children were each given a marshmallow and told that they can eat it anytime they want, but if they waited 15 minutes, they would receive another marshmallow. Follow-up studies showed that the results correlated well with these children's ...
The Monster Study was a non-consensual experiment performed on 22 orphan children in Davenport, Iowa in 1939 about stuttering.It was conducted by Wendell Johnson, University of Iowa, with the physical experiment being performed by his graduate student Mary Tudor.
A highly indicative test of changes in allele frequencies is the QTL sign test, and other tests include the Ka/Ks ratio test and the relative rate test. The QTL sign test compares the number of antagonistic QTL to a neutral model, and allows for testing of directional selection against genetic drift . [ 11 ]