Error that concludes that someone is not guilty, when in fact, they really are. (Ha true, but I concluded Ho).

BETA

Accept an hypothesis or statement as true when it is false: Ho is false, but I conclude Ho is true. Error that concludes that someone is not guilty, when in fact, he or she really is (accept Ho as true, beeing false, when Ha is true).

A failed alarm is a Type II error

BETA is the probabilty of error type II

Also known as consumer’s risk.