What is the difference between p-value and significance level?

The p-value is a measure that indicates the probability of obtaining test results at least as extreme as the observed results, assuming the null hypothesis is true. The significance level, often denoted as alpha (α), is a predetermined threshold set by the researcher (commonly 0.05) to decide whether to reject the null hypothesis. If the p-value is less than or equal to the significance level, the results are considered statistically significant, leading to the rejection of the null hypothesis. Essentially, the p-value is the outcome of the statistical test, while the significance level is the criterion for making a decision based on that outcome.