Type I error
Citation, DOI & article data
Type I errors (alpha errors, α) occur when we accept that there is a difference between two experimental groups, when in fact, no difference exists.
The threshold for accepting a type I error is the p-value. The traditionally accepted p-value of 0.05 indicates that the researchers are willing to take a ≤5% chance that the outcome of their data showing a difference between two groups was merely due to chance.
If multiple tests are compared, the risk of type I error increases.
Good statistical technique attempts to keep the risk of type I error as low as possible.