Mike concluded that there were no differences in self-confidence between those who had received his intervention and those in the control group. However, there were true differences, and Mike's intervention did actually work. Mike's conclusion represents
A) a Type I error.
B) a Type II error
C) both a Type I and Type II error.
D) a Type III error.

Question

Quizplus · Accepted Answer

Mike's conclusion that there were no differences in self-confidence between the intervention and control groups when there were actually differences represents a Type II error. This means that Mike incorrectly failed to reject the null hypothesis, which in this case would be that the intervention had no effect on self-confidence.

Mike Concluded That There Were No Differences in Self-Confidence Between