Editing Alternative hypothesis (section)

==Types==
In the case of a scalar parameter, there are four principal types  of alternative hypothesis:
* ''Point''. Point alternative hypotheses occur when the hypothesis test is framed so that the population distribution under the alternative hypothesis is a fully defined distribution, with no unknown parameters; such hypotheses are usually of no practical interest but are fundamental to theoretical considerations of [[statistical inference]] and are the basis of the Neyman–Pearson lemma.
* ''One-tailed directional''. A one-tailed directional alternative hypothesis is concerned with the region of rejection for only one tail of the sampling distribution.
* ''Two-tailed directional''. A two-tailed directional alternative hypothesis is concerned with both regions of rejection of the sampling distribution. 
* ''Non-directional''. A non-directional alternative hypothesis is not concerned with either region of rejection; rather, it is only concerned that null hypothesis is not true.