Difference Between Null and Alternative Hypothesis

Null vs Alternative Hypothesis

Scientific method explores the best possible and dependable explanation for a particular phenomenon. Based on the evidences and opinions, a hypothesis is created as the first step of the scientific method, to predict the possible outcome of a particular phenomenon. However, there is a possibility for the created hypothesis to be either accepted or rejected, based on the results obtained through the methodology of the study carried out. Therefore, the alternative hypothesis is presented in order to evade possible erratic explanations.

What is Null Hypothesis?

Null hypothesis is typically the default or the usual prediction that would be tested in the scientific method. The null hypothesis is laid out with a negative relationship; i.e. as if there is no relationship between the two studied processes. As an example, a proper null hypothesis of a study that tests the effect of a certain treatment over a disease would be stated as if there is no effect from the particular treatment on activity of the disease.

The null hypothesis is denoted as H0 when it is written. The alternative hypothesis is laid out usually against the null hypothesis. Since the null hypothesis is presented with the negation, it cannot be proven using the results. The results obtained for a particular test could only reject the null hypothesis. However, if there is no relationship between the measured parameters, the null hypothesis is not rejected. However, it does not mean that the H0 is accepted. In addition, the rejection or not rejection is entirely dependent on the statistical significance of the obtained results. That means the results of a particular test should be statistically significant to be the null hypothesis to be rejected.

What is Alternative Hypothesis?

Alternative hypothesis is simply the hypothesis that predicts anything other than the null hypothesis does. In the scientific method, an alternative hypothesis is presented that is usually the opposite of the null hypothesis. The alternative hypothesis is usually denoted as H1. In case of the null hypothesis is rejected, the alternative hypothesis is used to explain the tested phenomenon. However, the alternative hypothesis is not used to describe the phenomenon when the null hypothesis is not rejected.

When the null hypothesis predicts how a particular process is being operated the alternative hypothesis predicts the other possible outcomes. However, the alternative hypothesis may not always be the negation of the null hypothesis, but it provides a measurement to what extent the null hypothesis is close to the real explanation.

What is the difference between Null and Alternative Hypothesis?

• The two hypotheses are denoted differently with H0 for the null hypothesis and H1 for the alternative hypothesis.

• Null hypothesis is formulated first, and the alternative hypothesis is formed after that.

• Null hypothesis is the default prediction that a scientific study formulates while the alternative hypothesis is anything other than the H0.

• Most of the time, scientific studies test whether it would be possible to reject the null hypothesis and to use the alternative hypothesis to describe the phenomenon.