P-Value Explained Simply: What Does a P-Value Mean in Hypothesis Testing?

A p-value (probability value) is a number between 0 and 1 that measures the strength of evidence against the null hypothesis (H₀) in a statistical test.

• Small p-value (≤ 0.05): Strong evidence against H₀. Reject the null hypothesis — the result is statistically significant.
• Large p-value (> 0.05): Weak evidence against H₀. Fail to reject the null hypothesis — the observed difference could be due to random chance.

In most scientific fields, the standard significance threshold (alpha α) is set to 0.05 (5%).