Dina basa sejen, anggapan yen null hypothesis sederhana ditolak lamun tes [[statistic]] ''T'' leuwih gede tinimbang nilai kritis ''c''. Kira-kira dina sabagean kasus T nu di-observasi sarua jeung t<sub>observed</sub>. Mangka nilai-p tina T dina eta kasus probabiliti yen T bakal sarua atawa leuwih ti t<sub>observed</sub>.
The p-value does not depend on unobservable parameters, but only on the data, i.e., it is observable; it is a "statistic." In classical frequentist inference, one rejects the null hypothesis if the p-value is smaller than a number called the ''level'' of the test. In effect, the p-value itself is then being used as the test statistic. If the level is 0.05, then the probability that the p-value is less than 0.05, given that the null hypothesis is true, is 0.05, provided the test statistic has a continuous distribution. In that case, the p-value is [[