Rachid Bekani

I purchased the IASSC Black Belt Evaluation Exam one question in the set said :

From this control chart with a center line indicated by line number 4, which of the following observation numbers is more than 2 sigma from the mean?

the proposed  answers are :

A) 5
B)9
C) 13
D) 15
E)17
F)23

trying to synthesize the elements to…[Read more]