Type I and Type II Errors

Type I and Type II errors are concepts used in hypothesis testing. A Type I error occurs when we mistakenly reject a true hypothesis, essentially saying something is true when it is not – like claiming a new medicine works when it actually doesn't. Conversely, a Type II error happens when we fail to reject a false hypothesis, meaning we conclude that something doesn’t work when it actually does – like saying the medicine doesn’t work when it really does. In essence, a Type I error is a false positive, while a Type II error is a false negative.