Oliver 75 - 3rd Question

oberoi.amit
Contributor
Posts: 125
Joined: Mon Mar 24, 2014 5:14 am

Oliver 75 - 3rd Question

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.

Answer is B- A special cause should be investigated, the process should be adjusted.

I chose A, because I don't see any rule of Seven or any data going out of control beyond the given limits..
kripakrish
Beginner
Posts: 41
Joined: Wed Apr 09, 2014 2:59 pm

Re: Quality Mgmt

There are seven consecutive points on one side of the mean .So my guess is A special cause should be investigated, the process should be adjusted
namita
Super Member
Posts: 502
Joined: Wed Dec 11, 2013 10:25 am

Re: Quality Mgmt

Please confirm what 7 entries are on one side. Also second value is 19,995 and not 19.995. NOt sure if that is a typo. Check question
jyotimayank
Expert
Posts: 521
Joined: Mon Mar 09, 2015 6:01 am

Re: Oliver 75 - 3rd Question

Considering 19,995 as 19.995, the correct answer is option B.

Control charts are used to show whether a repetitive process is “in control” or “out of control” .When 7 consecutive data points are presented on either side of mean, then “process is considered Out of Control” based on heuristic of Rule of Seven.
Refer to Page 238 0f PMBOK® Guide 5th Edition

For more insight of this topic refer to the following blog

http://www.izenbridge.com/blog/control- ... lity-tool/
Jyoti Gupta
PMP Mentor & Coach

iZenbridge Consultancy Pvt Ltd