The alternative hypothesis (H A) is the other answer to your research question. It claims that there’s an effect in the population. Often, your alternative hypothesis is the same as your research hypothesis. In other words, it’s the claim that you expect or hope will be true. The alternative hypothesis is the complement to the null hypothesis.

The alternative hypothesis is one of two mutually exclusive hypotheses in a hypothesis test. The alternative hypothesis states that a population parameter does not equal a specified value. Typically, this value is the null hypothesis value associated with no effect, such as zero.

The alternative hypothesis and null hypothesis are types of conjectures used in statistical tests, which are formal methods of reaching conclusions or making judgments on the basis of data. In statistical hypothesis testing, the null hypothesis and alternative hypothesis are two mutually exclusive statements.

The alternate hypothesis is usually what you will be testing in hypothesis testing. It’s a statement that you or another researcher) thinks is true and one that can ultimately lead you to reject the null hypothesis and replace it with the alternate hypothesis.