# alternative hypothesis

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## 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.

## al·ter·na·tive hy·poth·e·sis

in Neyman-Pearson testing of a hypothesis, the hypothesis or family of hypotheses about the numerical value of a parameter if and only if the null hypothesis is rejected as untenable.

## alternative hypothesis

EBM
A statement that the means, variance, etc., of the samples being tested are not equal, which is the opposite of a null hypothesis.

Epidemiology
A hypothesis to be adopted if a null hypothesis proves implausible, where exposure is linked to disease.

Oncology
A hypothesis of tumour biology which holds that cancer is a systemic disease for which locoregional therapy is unlikely to improve survival statistics.

Statistics
A statement which is true if the null hypothesis is false; the type of test—left, right or two-tail—is based on the alternative hypothesis.

## alternative hypothesis

Epidemiology A hypothesis to be adopted if a null hypothesis proves implausible, where exposure is linked to disease. See Hypothesis testing. Cf Null hypothesis.

## alternative hypothesis

The possibility (which should always be borne in mind) that an explanation of a phenomenon or result, however apparently obvious, may not be correct. See also NULL HYPOTHESIS.
References in periodicals archive ?
Mean LR test RMSEA Statistic for N = 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1,000 for k = 10, 20, 30, 40, and 50 Items under the Null Hypothesis Condition (left panel) & Alternative Hypothesis Condition (right panel) with 8 DIF Items.
Consider the fixed noncentrality parameter in (58) and relation with system innovation information of alternative hypothesis in (46); accordingly the MDB is then calculated by
First, however, the next subsection discusses the alternative hypothesis in tests with three firms.
The form of the null and alternative hypothesis governs whether the testing is one-tailed or two-tailed.
Thus the null hypothesis that Acceptability of French as a second official language will not be higher among Nigerians who have business interests with French speaking countries is rejected while the alternative hypothesis that Acceptability of French as a second official language will be higher among Nigerians who have business interests with French speaking countries is accepted.
Research hypothesis : It is similar to the alternative hypothesis.
05 only for Lack of planning by using scenarios (a =0,021), which means that the relationship between the two variables is considered significant It follows that the alternative hypothesis is accepted, namely the respondents'age has significant influence on the factor mentioned.
We proposed a null hypotheses that average values do not vary with gender, type of study, year of study and average exam grade, and an alternative hypothesis that they do vary.
1) An alternative hypothesis, at least for patients with infiltrative diseases of the bone marrow, is that alteration of the bone marrow microenvironment leads to premature exit of immature hematopoietic cells from the bone marrow, with their accumulation at extramedullary anatomic sites.
The alternative hypothesis is that the impact of FRD on TFP is positive or negative.
In examples of one-sided alternative hypothesis on page 110, the statement [[bar.

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