a research hypothesis; the hypothesis that is supported if the null hypothesis is rejected.

In general, the proposition expressing the particular way the null hypothesis is held to be false. Sometimes referred to as the motivated hypothesis, it usually reflects a difference the researcher hopes to demonstrate. In the ANOVA setting, the usual alternative hypothesis is that the true means of the various groups are unequal.

Sometimes we propose an alternative to the null hypothesis, to be accepted if the null hypothesis is rejected. If the null hypothesis is that the mean is three, we reject it if the mean is not three. The alternative hypothesis may state that the mean is 3.5. Note that it is possible to reject both the null and alternative hypotheses. (The statement that the mean is not equal to three is known as the complement of the null hypothesis.)

a negation of the null hypothesis

(abbreviated H1 or Ha). A statement about a probabilistic model that will be asserted if the null hypothesis is rejected. Typically, the alternative hypothesis will include a range of possibilites ("composite alternative"), each of which is loosely called an alternative. (The special and rarely-occuring case in which the alternative hypothesis encompasses only one possibility is called a simple alternative.)

the prediction that is not tentatively held to be true; it states that a relationship will be found between two variables, or that the means of multiple groups are not equal.

The hypothesis that is accepted if the null hypothesis is rejected, usually represented by the symbol H1. Also known as the experimental or research hypothesis. The alternative hypothesis usually states that the independent variable has had an effect on the dependent variable that cannot be explained by chance alone. ( N.B. You never prove that the alternative hypothesis is correct, even if the null hypothesis is rejected, there is always a chance that you have wrongly rejected it.)

1. In a trial, the alternative hypothesis might be that a treatment of unknown efficacy has more benefit than the standard treatment. The alternative hypothesis is an alternative to the null hypothesis of no difference that specifies some true underlying difference of set of differences between two or more populations or groups with regard to some function, trait, characteristic, or effect. It may be stated in such a way so as to be concerned with a difference(s) in only one direction (one-sided alternative hypothesis) or in either direction (two-sided alternative hypothesis) relative to the null value. 2. Alternative treatment hypothesis.

(H1) A prediction that there is a difference between the groups of data being compared. The alternative hypothesis is often the working hypothesis, or research question, in a study.

In hypothesis testing, a null hypothesis (typically, that there is no effect) is compared with an alternative hypothesis (typically, that there is an effect, or that there is an effect of a particular sign). For example, in evaluating whether a new cancer remedy works, the null hypothesis typically would be that the remedy does not work, while the alternative hypothesis would be that the remedy does work. When the data are sufficiently improbable under the assumption that the null hypothesis is true, the null hypothesis is rejected in favour of the alternative hypothesis.

A precise statement relating to the research question to be tested, expressed in terms which assume a relationship (association) or difference between variables. Used in conjunction with a suitable null hypothesis. (See the issues of quantitative analysis for more information.)

The experimental hypothesis that predicts a statistically significant result. It is the opposite to the null-hypothesis, which predicts a non-significant result.

Any negation of the null hypotheses. For example, if the null hypothesis is "mean 1 is equal to mean 2". The alternative hypothesis are "mean 1 is not equal to mean 2" and mean 1 is greater than/less than mean 2."

The opposite of the null hypothesis. It is the conclusion when the null hypothesis is rejected.