Alpha risk is defined as the risk of rejecting the Null hypothesis when in fact it is true.

Synonymous with: Type I error, Producers Risk

In other words, stating a difference exists where actually there is none. Alpha risk is stated in terms of probability (such as 0.05 or 5%).

The value (1-alpha) corresponds to the confidence level of a statistical test, so a level of significance alpha = 0.05 corresponds to a 95% confidence level.