experimental hypothesis

the statement that there will be a statistically significant difference between the EXPERIMENTAL GROUP and the CONTROL GROUP, and that this difference will have been caused by the INDEPENDENT VARIABLE under investigation.

When an experiment is set up, or observational data collected, this is done in order to test a hypothesis, or theory, which has been developed from previous work. This is the experimental hypothesis, which states what the expected difference is between the groups if the theory is correct. The converse hypothesis, or NULL HYPOTHESIS, is also conventionally stated -that the predictions from the theory are incorrect. See also DEPENDENT VARIABLE, EXPERIMENTAL METHOD.

Collins Dictionary of Sociology, 3rd ed. © HarperCollins Publishers 2000

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The probability of the experimental hypothesis has been deduced (p = 0.001) 5.

Interpretation of the p value: a national survey study in academic psychologists from Spain/Interpretacion del valor p: una encuesta nacional entre profesores espanoles de Psicologia

To avoid possible variations in the confederates' behavior according to the experimental conditions, the confederates were not informed of the experimental hypothesis.

Effect of wearing eyeglasses on judgment of socioprofessional group membership

If the null hypothesis that the results are due to chance is rejected, the experiment is interpreted as providing evidence for the alternative or experimental hypothesis. Thus, the experiment has two possible outcomes--the null hypothesis is either accepted or rejected.

Beware of inferential errors and low power with Bayesian analyses: power analysis is needed for confirmatory research/Attention aux erreurs inferentielles etaux faibles puissances dans les analyses bayesiennes: l'analyse de puissance est necessaire pour la recherche confirmatoire/Vorsicht vor inferenzfehlern und geringer teststarke bei bayesschen analysen: eine analyse der teststarke wird bei bestatigungsforschung benotigt ..

To avoid possible variations in the confederates' behavior according to the experimental conditions, the confederates were not informed about the experimental hypothesis. A pre-test was conducted in the street in order to train the confederates in the use of the procedure and to verify that they acted in the same way in the three experimental conditions.

Brief report: women's hair color and donations: blonds receive more money

However, the experimental hypothesis was not supported by the other two trials.

The effect of clarinet reed hardness on bacterial growth. (South Carolina Junior Academy Of Sciences Abstracts)

Therefore, researchers need to aim for the highest power they can achieve, as the failure to utilize an adequate level of power in a statistical test increases the danger of needlessly rejecting an experimental hypothesis.

The account taken of statistical power in research published in the 'British Journal of Psychology.'

If the probability or p value of the observed outcome under this null hypothesis is less than a prespecified criterion, the outcome is interpreted as a significant result that provides evidence for the alternative or experimental hypothesis.

Bayesian and classical hypothesis testing: practical differences for a controversial area of research/Pruebas de hipotesis bayesiana y clasica: diferencias practicas para un area de investigacion pol'emica/ Le test d'hypotheses bayesien et classique: differences pratiques dans un champ de recherche controverse/ Bayessche und klassische hypothesenprufung: praktische unterschiede fur ein kontroverses ..

These results support the experimental hypothesis that caffeine and ephedra do enhance total amount of exercise and total time of exercise.

Effect of a caffeine/ephedra mixture on voluntary physical activity and body weight in mus musculus

Nonsignificant results could be due to the lack of power or to the experimental hypothesis being false.

Correspondence

Therefore, the experimental hypothesis was not supported.

The effect of various concentrations of Barley straw on the inhibition of green algae growth in pond water

An underpowered study is a biased form of research because it cannot provide basic evidence that the experimental hypothesis is false.

Can parapsychology move beyond the controversies of retrospective meta-analyses?/Est-ce que la parapsychologie peut sortir des controverses sur les meta-analyses retrospectives?/?Puede la parapsicologia superar las controversias de los metanalisis retrospectivos?/Kann die parapsychologie die kontroversen um retrospektive metaanalysen uberwinden?

The results of a two-way ANOVA indicated that the null hypothesis which stated that the chicken skin would not absorb more arsenic over increased periods of time was rejected, and the experimental hypothesis was supported.

The effect of time of exposure and concentration of CCA preservative on the amount of arsenic absorbed into chicken skin from pressure-treated lumber