Can the alternative hypotheses be true and false?

Yes, the alternative hypothesis can be either true or false, depending on the context of the study or experiment. In hypothesis testing, the alternative hypothesis represents a statement that contradicts the null hypothesis; thus, only one can be true at a given time. If the alternative hypothesis is true, it suggests that there is a significant effect or difference, while if it is false, it indicates that the null hypothesis holds true. Ultimately, statistical tests aim to gather evidence to support one hypothesis over the other.