We'd like to use analytics cookies to understand which symbols people look up, so we know what to research next. They are not used for advertising and we set none of them unless you say yes. What we store.
A lower-case p followed by a probability, reporting how surprising a result would be.
Also known as: p value, Significance value
A p-value is the probability of seeing data at least as extreme as the observed data, if the null hypothesis were true. It is not the probability that the hypothesis is false — a misreading so common that statistical bodies have issued statements about it.
Reports the probability of obtaining a result at least as extreme as the one observed, assuming the null hypothesis is true.
Contexts: Mathematics
Widely misread as the probability that the null hypothesis is true, or that the result occurred by chance. It is neither, and the misreading is the subject of formal statements by professional statistical associations.
Recorded because the misreading is near-universal outside statistics, not because it is a legitimate second meaning.
The conventional threshold of 0.05 is a convention with no theoretical basis, chosen for convenience and criticised on those grounds for as long as it has been used.
A lower-case italic letter p, followed by a comparison sign and a decimal figure.
The p-value is computed under the null hypothesis; neither means anything without the other.