DSST Principles of Statistics Exam Prep

Answer: B - A Type I error is the probability of rejecting the null hypothesis when it is true.

Key Takeaway: A Type I error in hypothesis testing is the probability of rejecting the null hypothesis when it is true. In this example, it is the probability that research will show that the knee joint replacement is causing nerve damage when it is not. Instead of accepting the null hypothesis of no damage, the researchers make a mistake of rejecting it and concluding that the replacement does cause damage.