hypothesis


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Related to hypothesis: Null hypothesis, Hypothesis testing, research hypothesis

hypothesis

 [hi-poth´ĕ-sis]
a supposition that appears to explain a group of phenomena and is advanced as a bases for further investigation.
alternative hypothesis the hypothesis that is formulated as an opposite to the null hypothesis in a statistical test.
complex hypothesis a prediction of the relationship between two or more independent variables and two or more dependent variables.
directional hypothesis a statement of the specific nature (direction) of the relationship between two or more variables.
Lyon hypothesis a hypothesis about development of X chromosomes in the embryo; see lyon hypothesis.
Monro-Kellie hypothesis [mun-ro´ kel´e] an explanation of the maintenance of intracranial pressure: The skull is viewed as a closed container housing brain tissue, blood, and cerebrospinal fluid; a change in any of these three components will affect the other two. If the volume added to the cranial vault is equal to the volume displaced, the intracranial volume will not change.
nondirectional hypothesis a statement that a relationship exists between two variables, without predicting the exact nature (direction) of the relationship.
null hypothesis the hyothesis that the effect, relationship, or other manifestation of variables and data under investigation does not exist; an example would be the hypothesis that there is no difference between experimental and control groups in a clinical trial.
hypothesis test the abstract procedure that is the theoretical basis of most statistical tests. A hypothesis test decides between two hypotheses, the null hypothesis (H0) that the effect under investigation does not exist and the alternative hypothesis (H1) that some specified effect does exist, based on the observed value of a test statistic whose sampling distribution is completely determined by H0. The decision is made to reject H0 and by implication to accept H1 when the test statistic falls within a given set of values called the critical region. This region is so determined that the probability of rejecting H0 when it is in fact true (a so-called Type I error, the reporting as significant results that are only the result of random variation and not a real effect), is set at a specified level (symbol α). When this level is set before the data are collected, usually at 0.05 or 0.01, it is called the significance level or α level. It is now more common to report the smallest α at which the null hypothesis can be rejected; this is called the significance probability or P value. The ability of the test to accept a true alternative (and thus to detect a real effect when it exists) is termed the power of the test. Note that no statistical test actually tests the H1.

hy·poth·e·sis

(hī-poth'ĕ-sis),
A conjecture advanced for heuristic purposes, cast in a form that is amenable to confirmation or refutation by conducting of definable experiments and the critical assembly of empiric data; not to be confused with assumption, postulation, or unfocused speculation.
See also: postulate, theory.
[G. foundation, assumption fr. hypotithenai, to lay down]

hypothesis

/hy·poth·e·sis/ (hi-poth´ĕ-sis) a supposition that appears to explain a group of phenomena and is advanced as a basis for further investigation.
alternative hypothesis  one that is compared with the null hypothesis in a statistical test.
biogenic amine hypothesis  the hypothesis that depression is associated with deficiency of biogenic amines, especially norepinephrine, at functionally important receptor sites in the brain and that elation is associated with excess of such amines.
jelly roll hypothesis  a theory explaining the formation of nerve myelin, which states that it consists of several layers of the plasma membrane of a Schwann cell wrapped spirally around the axon in a jelly roll fashion.
lattice hypothesis  a theory of the nature of the antigen-antibody reaction which postulates reaction between multivalent antigen and divalent antibody to give an antigen-antibody complex of a lattice-like structure.
Lyon hypothesis  the random and fixed inactivation (in the form of sex chromatin) of one X chromosome in mammalian cells at an early stage of embryogenesis, leading to mosaicism of paternal and maternal X chromosomes in the female.
null hypothesis  the particular one under investigation, which frequently asserts a lack of effect or of difference.
one gene–one polypeptide chain hypothesis  a gene is the DNA sequence that codes for the production of one polypeptide chain. Antibodies are an exception; separate genes for variable and constant regions are rearranged to code for a single polypeptide.
response-to-injury hypothesis  one explaining atherogenesis as initiating with some injury to the endothelial cells lining the artery walls, which causes endothelial dysfunction and leads to abnormal cellular interactions and initiation and progression of atherogenesis.
sliding filament hypothesis  the stretching of individual muscle fibers raises the number of tension-developing bridges between the sliding contractile protein elements (actin and myosin) and thus augments the force of the next muscle contraction.
Starling's hypothesis  the direction and rate of fluid transfer between blood plasma in the capillary and fluid in the tissue spaces depend on the hydrostatic pressure on each side of the capillary wall, on the osmotic pressure of protein in plasma and in tissue fluid, and on the properties of the capillary walls as a filtering membrane.
wobble hypothesis  one describing how a specific transfer RNA (tRNA) molecule can translate different codons in a messenger RNA (mRNA) template. It states that the third base of the tRNA anticodon does not have to pair with a complementary codon (as do the first two) but can form base pairs with any of several related codons.

hypothesis

(hī-pŏth′ĭ-sĭs)
n. pl. hypothe·ses (-sēz′)
1. A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation.
2. Something taken to be true for the purpose of argument or investigation; an assumption.
3. The antecedent of a conditional statement.

hypothesis

[hīpoth′isis]
Etymology: Gk, groundwork
(in research) a statement derived from a theory that predicts the relationship among variables representing concepts, constructs, or events. Kinds of hypotheses include causal hypothesis, null hypothesis, and predictive hypothesis.

hypothesis

Epidemiology A supposition, arrived at from observation or reflection, that leads to refutable predictions; a conjecture cast in a form that will allow it to be tested and refuted

hy·poth·e·sis

, pl. hypotheses (hī-poth'ĕ-sis, -sēz)
A conjecture cast in a form that is amenable to confirmation or refutation by experiment and the assembly of data; not to be confused with assumption, postulation, or unfocused speculation.
See also: postulate, theory
[G. foundation, assumption fr. hypotithenai, to lay down]

hypothesis

A tentative proposition used as a basis for reasoning or experimental research, by means of which it may be rejected or incorporated into accepted knowledge. See NULL HYPOTHESIS.

hypothesis

a proposition assumed on the basis of observation which might account for or explain something which is not fully understood. see SCIENTIFIC METHOD.

hypothesis

a provisional or tentative theory, not yet supported by a significant amount of corroborative evidence.

hypothesis

theory unsupported by substantiated facts or data that would prove or deny its truth; null and alternate hypotheses are compared by statistical tests, and probability (that an observed effect is true or not) is determined by statistical evaluation of P -value
  • alternative hypothesis; research hypothesis assumption that any difference noted (within a variable under different conditions) has occurred as the direct result of the observed or imposed changes

  • null hypothesis assumption that any difference noted (within a variable under different conditions) has occurred by chance

hypothesis,

n an experimentally testable proposal given as the basis for additional examination.

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.

hy·poth·e·sis

, pl. hypotheses (hī-poth'ĕ-sis, -sēz)
A conjecture advanced for heuristic purposes, cast in a form that is amenable to confirmation or refutation by conducting of definable experiments and the critical assembly of empiric data.
See also: theory
[G. foundation, assumption fr. hypotithenai, to lay down]

hypothesis

a supposition that appears to explain a group of phenomena and is assumed as a basis of reasoning and experimentation.

hypothesis testing
a standard practice using statistical methods, usually analytical observational studies, to differentiate between two hypotheses. For example, the user assumes that vaccination against a particular disease reduces the prevalence of the disease, then tests that hypothesis.
hypothesis testing sampling
sampling of material or data for the purpose of testing a hypothesis.
References in periodicals archive ?
Based on the t statistics of perceived quality is at the 99 percent of confidence level and has significant impact on relation quality, so the first hypothesis is confirmed.
of an informative hypothesis is a directional one-sided hypothesis,
In both functional hypothesis and treatment measures, Helen is the most difficult case as measured by student performance.
An example of a working hypothesis might be: A blood draw this morning caused the bruise on Resident Mary Hughes's arm.
A test is based on the prior assertion that if a given hypothesis is true, the data generating process will produce a value of the selected statistic that falls into the rejection region with probability equal to the corresponding significance level, which typically corresponds to a p-value smaller than the significance level.
In an attempt to overcome this total lack of evidence, some evolutionists in a 1980 meeting in Chicago suggested a "punctuated equilibria" hypothesis.
Conferees generally supported the hypothesis that early exposures to environmental toxicants could later affect the brain and that such associations are biologically plausible (De la Fuente-Fernandez and Calne 2002).
Such a pattern would seem more consistent with our STI hypothesis than with a direct hormonal effect on TB disease progression rates.
To address the problems associated with the null hypothesis inference testing model, psychology and related fields are starting to move in the direction of placing more emphasis on practical significance, the degree of relationship between variables, or the magnitude of the effect, instead of tests of statistical significance.
Secondary issues examine contract formation, terms of an agreement, breach of contract, misrepresentation and legal remedies, as well as ethical issues related to business conduct affecting consumers and statistical analysis involving hypothesis testing which may lead to alternate business decisions.
Instead of seeing justice as a rational solution to the natural condition of fear and conflict, O'Manique presents evidence to support the hypothesis that human rights, law, and justice arise within caring communities, from the reflections of our early ancesters on genetically based inclinations required for biological development.
Maybe I'm missing something, but it seems to me that the only viable hypothesis left thing, but it seems to me that the only viable hypothesis left is something like the following: There is a statistical association between the qualities that make for good academics and those that lead to left-leaning political views.