# significance

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Related to significance: significance level

## significance

Clinical medicine A finding to be weighed in establishing a diagnosis, or influencing management of, a clinical state, which may be expressed as a finding of significance  Statistics A measure of deviation of data from a statistical mean, defined by a probability–p value, where a p of 0.05 indicates a 5% possibility or 1 chance in 20 that a dataset differs from a mean and 19 chances that it will not. See Clinical significance, Statistical significance.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

## significance

(statistics) a description of an observed result that shows sufficient deviation from the result expected to be considered different from the expected result. Significance tests such as the CHI-SQUARED TEST can be carried out to produce a value that is converted into the probability that an observed result will match the result expected from a theory. In biology there is a convention that, if there is more than a 5% chance (P < 5%) that the observed result is the same as the expected, it is possible to conclude that any deviations are ‘not significant’, i.e. have occurred by chance alone. If, however, there is less than a 5% chance (P < 5%) that observed and expected are the same, then it is concluded that the deviations are ‘significant’, i.e. have not occurred by chance alone. For example, tossing a coin 100 times gives 58 heads and 42 tails. The probability that 58:42 is similar to the expected 50:50 is greater than 5%, thus we can conclude that there is no significant deviation between observed and expected results.
Collins Dictionary of Biology, 3rd ed. © W. G. Hale, V. A. Saunders, J. P. Margham 2005

## significance

In statistics, an indication that the results of an investigation on a population (e.g. patients) differ from those of another population (e.g. general) by an amount that could not happen by chance alone. This is evaluated by establishing a significance level, that is the probability, called p value, which leads us to reject or accept the null hypothesis Ho (there is no significant difference between two populations and the difference is attributed to chance) and accept or reject the alternative hypothesis H1 that there is a statistically significant difference between two populations. A p value p < 0.05 is often considered significant, but the lower this figure, the stronger the evidence. See randomized controlled trial.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann
References in periodicals archive ?
The test for significance is based on whatever statistical test was done in the study.
In terms of the information that an applicant for a proposal will need to provide, this must be proportionate to the significance of the asset and the potential impact of the proposal.
Statistical significance is not the same thing as scientific finding." A scientific study is concerned with determining the magnitude of effect, answering the question, "How much?" Contrast this with conclusions based solely on a statement of statistical significance.
The authors next consider whether the fetish of tests of significance is basically harmless--something that is just a ritual that perhaps makes quantitative research appear more scientific than is warranted.
65) notes, the process of determining an item's significance and the impact of this process have received scant attention from the library profession.
* Sports hall, owned by Middlesbrough Council - the buildings are detrimental to the appearance and significance of the site and should be demolished and redeveloped.
Hunter's valuable book will need to be incorporated into our understanding of the nature and social significance of girl's experiences--both within the circle of female relationships, and outside them.
However, it is common practice to instead compare a p-value to a significance level, rejecting the hypothesis if the p-value is smaller than the significance level.
The analyst adds that topline results were reported and speculates the negative overreaction in stock value is due to the lack of statistical significance for the primary endpoint.
Due to its significance to many of NTU's former students, an appeal to save the building was launched online.

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