What does the alpha level ($\alpha$) commonly set at 0.05 represent?

Answer

The maximum acceptable probability of incorrectly rejecting the null hypothesis (a Type I error).

The alpha level is the predetermined threshold for error researchers are willing to accept, defining the risk of concluding an effect exists when it does not (a false positive).

What does the alpha level ($\alpha$) commonly set at 0.05 represent?
SignificanceInterpretationeffectstatistic