# Type I error

- The statistical error (said to be "of the first kind" or alpha error) made in testing an hypothesis when it is concluded that a treatment or intervention is effective when it really is not. Sometimes referred to as a false positive.
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in a hypothesis test, the rejection of the null hypothesis when it is true; the probability of a Type I error (the significance level) is denoted by α.

*Medical dictionary.
2011.*

### Look at other dictionaries:

**Type I Error**— A type of error that occurs when a null hypothesis is rejected although it is true. The error accepts the alternative hypothesis, despite it being attributed to chance. Also referred to as a false positive . Type I error rejects an idea that… … Investment dictionary**Type II Error**— A statistical term used within the context of hypothesis testing that describes the error that occurs when one accepts a null hypothesis that is actually false. The error rejects the alternative hypothesis, even though it does not occur due to… … Investment dictionary**Type II error**— The statistical error (said to be "of the second kind" or beta error) made in testing an hypothesis when it is concluded that a treatment or intervention is not effective when it really is. Sometimes referred to as a false negative. * * … Medical dictionary**type I error**— noun Rejecting the null hypothesis when the null hypothesis is true. Syn: α error, alpha error, false positive, error of the first kind … Wiktionary**type II error**— noun Accepting the null hypothesis when the null hypothesis is false. Syn: β error, beta error, error of the second kind, false negative … Wiktionary**Type I error**— the error made in the statistical testing of a hypothesis by rejecting the null hypothesis when it is actually true. [1960 65] * * * … Universalium**Type II error**— the error made in the statistical testing of a hypothesis by accepting the null hypothesis when it is actually false. * * * … Universalium**type I error**— Stats an error arising from incorrectly rejecting the null hypothesis in a statistical study … The ultimate business dictionary**type II error**— Stats an error arising from incorrectly accepting the null hypothesis in a statistical study … The ultimate business dictionary**type I error**— ˌtīp¦wən noun : rejection of the null hypothesis in statistical testing when it is true * * * the error made in the statistical testing of a hypothesis by rejecting the null hypothesis when it is actually true. [1960 65] … Useful english dictionary