Type I error

American

noun

the error made in the statistical testing of a hypothesis by rejecting the null hypothesis when it is actually true.

type I error British

noun

statistics the error of rejecting the null hypothesis when it is true, the probability of which is the significance level of a result

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of Type I error

First recorded in 1960–65

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Type I error: This error results when a true null hypothesis is rejected.

From Textbooks • Mar. 27, 2020

Type I error: The null hypothesis claims that the tomato plant is alive, and it is true, but the students make the mistake of thinking that the plant is already dead.

From Textbooks • Mar. 27, 2020

If in fact this sample mean it did come from H0, but from in the tail, we have made a Type I error: we have rejected a good null.

From Textbooks • Nov. 29, 2017

The probability of making a Type I error is α.

From Textbooks • Nov. 29, 2017

A Type I error occurs when a true hypothesis is rejected, and a Type II error occurs when a false hypothesis is accepted.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023