Here is a question on Control Limits I am very confused with the answer
A production process has been defined as part of an industrial equipment manufacturing project. The process is intended to produce steel bolts with a length of 20 cm. The control limits are 19.955cm and 20.045cm.
The measurements made at the end of the process yielded the following results:
20.033cm, 19.982cm, 19,995cm, 20.006cm, 19.970cm, 19.968cm, 19.963cm, 19.958cm, 19.962cm, 19.979cm, 19.959cm.
What should be done?
A. The process is under control. It should not be adjusted.
B. A special cause should be investigated, the process should be adjusted.
c. The control limits should be adjusted.
D. The measuring equipment should be recalibrated.
I picked the answer A., Reason if 7 consecutive times if it goes out of limit, then it should be stopped and investigated.
But here it did'nt go 7 times out. so i chose A.
the answer chosen is B.(PMBOK® Guide 4th Edition, pp 196, 209)
Here is the link the question no: 3
http://www.oliverlehmann.com/pmp-self-test/75-free-questions.htm
Here is a question on Control Limits I am very confused with the
Hi cplusplus,
Rule of 7 didnt say that when 7 consecutive times if it goes out of limit, then it should be stopped and investigated. it says that - If there are seven points on one side of mean, then an assignable cause must be found.
Hope it will clarify.
Reg Control Limits
A process is considered not stable
a) When it is out of control limit
or b) Seven points are on either side of the mean
Rule of seven
In PMBOK Guide 4 page no 227 under top control charts its mentioned as process is out of control if seven consecutive points are above of below the mean.