The probability, when Ho is true, of a test statistic value at least as contradictory to Ho as the value actually observed.
- The smaller the P-value, the more strongly the data contradict Ho.
- The P-value summarizes the evidence in the data about the null hypothesis.
A moderate to large P-value means that the data are consistent with Ho. (fail to reject Null)
=>Ex. P-value .26 or .83 indicates that the observed data would not be unusual if Ho were true; However, a P-value such as .001 means that such data would be very unlikely, if Ho were true.
-The P-value is the primary reported result of a significance test. If the P-value is sufficiently small, one rejects Ho and accepts H1.