Flow of inferential testing

1. State the hypotheses: the null hypothesis ($H_0$) and the alternative hypothesis ($H_1$).
2. Collect sample data.
3. Calculate a test statistic.
4. Compare the test statistic with a critical value or check the $p$ value.
5. Decide whether to reject or retain $H_0$.

Inferential testing helps psychologists decide whether a pattern in sample data is likely to reflect a real effect in the wider population, rather than random variation. The starting point is always two hypotheses: the null hypothesis predicts no real effect, while the alternative hypothesis predicts an effect, difference, or relationship.