When a process is in control, it results in there being, on average, 16 defects per unit of output. chart limits of 4 and 28 would lead to a _____ percent chance of a Type I error.
A)68.26
B)95.44
C)31.74
D)0.26
E)4.56

Question

Quizplus · Accepted Answer

The correct answer is D because the probability of a Type I error is the probability of rejecting the null hypothesis when it is true. In this case, the null hypothesis is that the process is in control, and the alternative hypothesis is that the process is out of control. The probability of a Type I error is the area under the normal curve between the upper control limit (UCL) and the lower control limit (LCL). In this case, the UCL is 28 and the LCL is 4, so the probability of a Type I error is the area under the normal curve between 4 and 28. This area is approximately 0.26, or 2.6%.

When a Process Is in Control, It Results in There