Definition
The alternative hypothesis is a statement that contradicts the null hypothesis and represents the hypothesis that there is an effect or a difference.
It is what the researcher aims to provide evidence for.
Characteristics
Indicates an Effect: The alternative hypothesis suggests that any observed effect is real and not due to random chance.
Directionality: It can be one-sided (one-tailed) or two-sided (two-tailed), depending on the research question.
Formulation: It is often formulated to include inequality signs (e.g., ≠, <, >).
Pharmaceutical Example
Continuing with the clinical trial example, the alternative hypothesis might be:
This states that the mean outcome for the treatment group is different from that of the placebo group, indicating that the new drug has an effect.