P-value

How it is used

Compared with the significance level, usually 0.05. In APA style it is written as an italic p with no leading zero (p = .032, p < .001). Statisticians warn that a p-value is not the probability that the null hypothesis is true and says nothing about the size of an effect.

Example sentences

1. The p-value for the interaction term is 0.004, well below our 0.05 threshold.

2. A large p-value does not prove that there is no effect.

Common collocations

• report the p-value
• small p-value
• exact p-value
• adjusted p-value
• p-value threshold

Related terms

• statistical significanceThe conclusion that a result is unlikely to be due to chance alone, judged by comparing the p-value with a chosen significance level such as 0.05.
• significance levelThe threshold, chosen before a test, below which a p-value is treated as statistically significant; it is also the accepted risk of a Type I error.
• null hypothesisThe default claim in a statistical test that there is no effect, no difference or no relationship; the test checks whether the data give enough evidence against it.
• effect sizeA number that shows how large a difference or relationship is, independently of sample size, such as Cohen's d, a correlation coefficient or an odds ratio.
• type I errorRejecting a null hypothesis that is actually true, in other words concluding that an effect exists when it does not; a false positive.

This word in other fields

The same English word can have a different meaning in another field:

• p-value · Software Engineering
• p-value · Data Science & Analytics
• p-value · Academic English & Research

More terms: Hypothesis Testing

• hypothesis
• alternative hypothesis
• reject the null hypothesis
• t-test
• chi-square test
• ANOVA
• type II error
• statistical power
• degrees of freedom
• two-tailed test
• assumption
• nonparametric test