Dalam [[Uji hipotesis|pengujian hipotesis statistik]], '''nilai p''' atau '''nilai probabilitas''' atau '''signifikansi asimtotik''' adalah probabilitas untuk suatu model statistik dimana, apabila hipotesis nol benar, maka parameter (misalnya, perbedaan rata-rata sampel antara dua kelompok) akan sama dengan atau lebih besar daripada nilai yang sebenarnya.<ref name="ASA">{{Cite journal|last=Wasserstein|first=Ronald L.|last2=Lazar|first2=Nicole A.|date=7 March 2016|title=The ASA's Statement on p-Values: Context, Process, and Purpose|url=http://amstat.tandfonline.com/doi/full/10.1080/00031305.2016.1154108?scroll=top&needAccess=true|journal=The American Statistician|volume=70|issue=2|pages=129–133|doi=10.1080/00031305.2016.1154108|access-date=30 October 2016}}</ref> Penggunaan nilai p dalam pengujian hipotesis statistik seringkali digunakan dalam berbagai bidang penelitian<ref name="Bhattacharya2002">{{Cite journal|last=Bhattacharya|first=Bhaskar|last2=Habtzghi|first2=DeSale|date=2002|title=Median of the p value under the alternative hypothesis|url=http://www.tandfonline.com/doi/abs/10.1198/000313002146|journal=The American Statistician|publisher=American Statistical Association|volume=56|issue=3|pages=202–6|doi=10.1198/000313002146|access-date=19 February 2016}}</ref> seperti [[fisika]], [[Ilmu ekonomi|ekonomi]], [[keuangan]], [[ilmu politik]], [[psikologi]],<ref>{{Cite journal|last=Wetzels|first=R.|last2=Matzke|first2=D.|last3=Lee|first3=M. D.|last4=Rouder|first4=J. N.|last5=Iverson|first5=G. J.|last6=Wagenmakers|first6=E. -J.|year=2011|title=Statistical Evidence in Experimental Psychology: An Empirical Comparison Using 855 t Tests|journal=Perspectives on Psychological Science|volume=6|issue=3|pages=291–298|doi=10.1177/1745691611406923}}</ref> [[biologi]], [[kriminologi]], dan [[sosiologi]].<ref>Babbie, E. (2007). The practice of social research 11th ed. Thomson Wadsworth: Belmont, California.</ref>
