P-value

P-value or calculated probability is the value of probability of an event occurrence if a null hypothesis turns out to be true. It can also be interpreted the other way round, in the sense that p-value helps to determine if a null hypothesis is true or not. It is used to quantify the idea of the statistical significance of evidence. We compare the p-value with the critical value to reject or accept a null hypothesis.

• A small p-value (typically ≤ 0.05) indicates a strong evidence against the null hypothesis, so the null hypothesis can be rejected.

• A large p-value (> 0.05) indicates weak evidence against the null hypothesis, so the null hypothesis cannot be rejected.

• A p-value near 0.05 is considered to be marginal and the decision can go either way.