What is the definition of an alternative hypothesis?

The alternative hypothesis is fundamental in statistical hypothesis testing as it represents the claim or assertion that proposes a significant effect or difference exists in the population being studied. By expressing this idea, it directly opposes the null hypothesis, which generally posits that no such effect or difference is present. This makes it essential for researchers, as the alternative hypothesis drives the direction of their research and analysis.

In the context of hypothesis testing, if sufficient evidence is found through data analysis to reject the null hypothesis in favor of the alternative hypothesis, it suggests that the observed effects or differences are statistically significant, and not merely the result of random variation. Understanding this relationship is crucial for interpreting results correctly and for making informed decisions based on statistical data.