What is a p value? What does the p-value mean in words?

The p-value is the probability of obtaining test results at least as extreme as the observed results, assuming the null hypothesis is true. In plain language, a small p-value (typically ≤ 0.05) indicates that the observed data would be very unlikely if the null hypothesis were true, providing evidence to reject it.

In words: The p-value tells you how surprising your data would be if the null hypothesis were correct. The smaller the p-value, the more surprising the result and the stronger the evidence against the null hypothesis.

Hypothesis testing provides the context for interpreting p-values: "A hypothesis test is a decision-making process that examines a set or sets of data, and on the basis of expectation under null hypotheses, leads to a decision as to whether or not to reject null hypotheses."

Common significance thresholds: p < 0.05 (significant), p < 0.01 (highly significant), p < 0.001 (very highly significant).