Null vs Alternative Hypothesis
The scientific method aims to determine the most accurate and reliable explanation for a specific phenomenon. A hypothesis is developed as the first step of the scientific method to predict the possible outcome of a particular phenomenon. However, the hypothesis may either be accepted or rejected based on the study’s methodology and results. To avoid potential errors, an alternative hypothesis is introduced.
What is Null Hypothesis?
The null hypothesis is the default or standard prediction that is tested in the scientific method. It is framed with a negative relationship, suggesting that there is no association between the two studied processes. For example, a null hypothesis for a study examining the effect of a certain treatment on a disease might state that the treatment has no impact on the disease’s activity.
The null hypothesis is represented as H0 when written. The alternative hypothesis is typically presented against the null hypothesis. Since the null hypothesis is presented with negation, it cannot be proven using the results. The results for a particular test can only reject the null hypothesis. However, if there is no correlation between the measured parameters, the null hypothesis is not rejected. It does not mean that H0 is accepted, though. Furthermore, rejection or non-rejection depends entirely on the statistical significance of the obtained results. The results of a specific test must be statistically significant for the null hypothesis to be rejected.
What is Alternative Hypothesis?
The alternative hypothesis is a hypothesis that predicts something other than the null hypothesis. In the scientific method, an alternative hypothesis is presented that is typically the opposite of the null hypothesis. The alternative hypothesis is usually denoted as H1. If 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.
While the null hypothesis predicts how a specific process operates, the alternative hypothesis predicts 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 H0.
• Most of the time, scientific studies test whether it would be possible to reject the null hypothesis and use the alternative hypothesis to describe the phenomenon.
Key Takeaways
- Null hypothesis is the default prediction tested in the scientific method, while the alternative hypothesis is anything other than the null hypothesis.
- The null hypothesis is represented as H0, and the alternative hypothesis is denoted as H1.
- Null hypothesis is formulated first, and the alternative hypothesis is formed after that.
