Alternative hypothesis

From WikiMD's Wellness Encyclopedia

Alternative hypothesis

An alternative hypothesis is a key concept in statistical hypothesis testing. It is a statement that contradicts the null hypothesis and proposes that there is a statistically significant effect or relationship between variables in a study. The alternative hypothesis is denoted as H1 or Ha.

Formulation[edit | edit source]

In the context of hypothesis testing, researchers formulate the alternative hypothesis to test against the null hypothesis (H0). The null hypothesis typically states that there is no effect or no difference, while the alternative hypothesis suggests the presence of an effect or difference. For example, in a clinical trial, the null hypothesis might state that a new drug has no effect on a disease, whereas the alternative hypothesis would state that the drug does have an effect.

Types of Alternative Hypotheses[edit | edit source]

There are two main types of alternative hypotheses:

  • One-tailed alternative hypothesis: This hypothesis specifies the direction of the effect or relationship. For example, it might state that a new teaching method is better than the traditional method.
  • Two-tailed alternative hypothesis: This hypothesis does not specify the direction of the effect or relationship. It only states that there is a difference. For example, it might state that there is a difference in test scores between two teaching methods, without specifying which one is better.

Testing the Alternative Hypothesis[edit | edit source]

To test the alternative hypothesis, researchers use various statistical tests such as the t-test, chi-square test, and ANOVA. The choice of test depends on the type of data and the research design. The result of the test will either lead to the rejection of the null hypothesis in favor of the alternative hypothesis or fail to reject the null hypothesis.

Significance Level and P-Value[edit | edit source]

The significance level (α) is a threshold set by the researcher, commonly at 0.05, which determines the probability of rejecting the null hypothesis when it is actually true. The p-value is the probability of obtaining the observed data, or something more extreme, assuming the null hypothesis is true. If the p-value is less than the significance level, the null hypothesis is rejected, supporting the alternative hypothesis.

Related Concepts[edit | edit source]

See Also[edit | edit source]


Fisher iris versicolor sepalwidth.svg
   This article is a statistics-related stub. You can help WikiMD by expanding it!


WikiMD
Navigation: Wellness - Encyclopedia - Health topics - Disease Index‏‎ - Drugs - World Directory - Gray's Anatomy - Keto diet - Recipes

Search WikiMD

Ad.Tired of being Overweight? Try W8MD's physician weight loss program.
Semaglutide (Ozempic / Wegovy and Tirzepatide (Mounjaro / Zepbound) available.
Advertise on WikiMD

WikiMD's Wellness Encyclopedia

Let Food Be Thy Medicine
Medicine Thy Food - Hippocrates

Medical Disclaimer: WikiMD is not a substitute for professional medical advice. The information on WikiMD is provided as an information resource only, may be incorrect, outdated or misleading, and is not to be used or relied on for any diagnostic or treatment purposes. Please consult your health care provider before making any healthcare decisions or for guidance about a specific medical condition. WikiMD expressly disclaims responsibility, and shall have no liability, for any damages, loss, injury, or liability whatsoever suffered as a result of your reliance on the information contained in this site. By visiting this site you agree to the foregoing terms and conditions, which may from time to time be changed or supplemented by WikiMD. If you do not agree to the foregoing terms and conditions, you should not enter or use this site. See full disclaimer.
Credits:Most images are courtesy of Wikimedia commons, and templates Wikipedia, licensed under CC BY SA or similar.

Contributors: Prab R. Tumpati, MD