annotate this The use of P values (eg, P < .05), the term "statistically significant," and the array of statistical tests (eg, ANOVA, t-tests) all convey that investigators are testing a hypothesis to make an infer- ence about some population. To understand what these terms indicate, it is important to grasp that all such hy- potheses are attempts to refute, rather than prove, some- thing.12 This reasoning is at first counterintuitive but becomes clearer when the idea of the null hypothesis is fully understood