Alternate hypothesis

Jump to navigation Jump to search

WikiDoc Resources for Alternate hypothesis

Articles

Most recent articles on Alternate hypothesis

Most cited articles on Alternate hypothesis

Review articles on Alternate hypothesis

Articles on Alternate hypothesis in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Alternate hypothesis

Images of Alternate hypothesis

Photos of Alternate hypothesis

Podcasts & MP3s on Alternate hypothesis

Videos on Alternate hypothesis

Evidence Based Medicine

Cochrane Collaboration on Alternate hypothesis

Bandolier on Alternate hypothesis

TRIP on Alternate hypothesis

Clinical Trials

Ongoing Trials on Alternate hypothesis at Clinical Trials.gov

Trial results on Alternate hypothesis

Clinical Trials on Alternate hypothesis at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Alternate hypothesis

NICE Guidance on Alternate hypothesis

NHS PRODIGY Guidance

FDA on Alternate hypothesis

CDC on Alternate hypothesis

Books

Books on Alternate hypothesis

News

Alternate hypothesis in the news

Be alerted to news on Alternate hypothesis

News trends on Alternate hypothesis

Commentary

Blogs on Alternate hypothesis

Definitions

Definitions of Alternate hypothesis

Patient Resources / Community

Patient resources on Alternate hypothesis

Discussion groups on Alternate hypothesis

Patient Handouts on Alternate hypothesis

Directions to Hospitals Treating Alternate hypothesis

Risk calculators and risk factors for Alternate hypothesis

Healthcare Provider Resources

Symptoms of Alternate hypothesis

Causes & Risk Factors for Alternate hypothesis

Diagnostic studies for Alternate hypothesis

Treatment of Alternate hypothesis

Continuing Medical Education (CME)

CME Programs on Alternate hypothesis

International

Alternate hypothesis en Espanol

Alternate hypothesis en Francais

Business

Alternate hypothesis in the Marketplace

Patents on Alternate hypothesis

Experimental / Informatics

List of terms related to Alternate hypothesis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]


Overview

The alternate hypothesis (or maintained hypothesis or research hypothesis) and the null hypothesis are the two rival hypotheses whose likelihoods are compared by a statistical hypothesis test. Usually the alternate hypothesis is the possibility that an observed effect is genuine and the null hypothesis is the rival possibility that it has resulted from random chance.

The classical (or frequentist) approach is to calculate the probability that the observed effect (or one more extreme) will occur if the null hypothesis is true. If this value (sometimes called the "p-value") is small then the result is called statistically significant and the null hypothesis is rejected in favour of the alternate hypothesis. If not, then the null hypothesis is not rejected. Incorrectly rejecting the null hypothesis is a Type I error; incorrectly failing to reject it is a Type II error.

Bayesian statisticians would challenge this approach in that it takes no account of a priori beliefs in the two hypotheses or the different consequences of taking a wrong decision; there may be good reasons (extraneous to the statistical data) for believing the null hypothesis to be correct. This must be weighed against the damning evidence of a low p-value before the null hypothesis can be rejected.

An example: In the trial of Sally Clark, a solicitor accused of killing both her babies, pediatrician Sir Roy Meadow testified that the probability of two infants in the same family dying of natural causes was 1 in 73,000,000. If natural death is the null hypothesis and murder the alternate hypothesis, then the p-value is 1/73,000,000. The smallness of this value means that the null hypothesis that the deaths had had natural causes should be rejected and therefore murder concluded.

The problem was that even if the 73,000,000 figure were correct (this calculation was itself challenged as being flawed by the ecological fallacy), double murder is a rare event and there is therefore a good a priori reason for believing the null hypothesis. The standard hypothesis test was therefore not a good indicator of Clark's guilt.

Template:Statistics


Template:WikiDoc Sources