The threshold at which the decision is made to reject the null hypothesis. The smallest significance level that is normally regarded as reasonable evidence is 5%, which means that the probability of a false positive (or Type I error) is less than 1 in 20. There is now considerable debate on whether choosing such an arbitrary critical value is helpful. Instead it is suggested one should quote the exact p-value, allowing the reader to assess the strength of evidence this suggests.
Also used in hcistats2e: Chap. 6: pages 67, 68; Chap. 7: pages 84, 85, 86; Chap. 8: pages 88, 93, 94; Chap. 9: pages 104, 107, 108
Used in glossary entries: critical values, false positive, null hypothesis, p-value, significance level, Type I error