Just back from a trip to Patagonia and catching up with emails and writing this morning. Posting an article for this list is due today along with a touch of travel weariness, decided to share a part of a question received concerning data analysis.
My thought is to post an actual question one of our peers is facing, and meet the deadline for this post.
The Question
Rafael asked about the analysis of an experiment that included 8 failures out of 10 samples. He wrote, in part:
I’m testing 10 devices (non-repairable system) over e.g. 400 hrs.
Recorded failure times in hrs: {30, 45, 60, 90, 120, 180, 240, 300}, 2 devices survived.
Let’s assume the two censored devices ran for 400 hours.
How would you report the results of this experiment?
Other Questions to Consider
When I first looked at this request, I wondered what was important. Not knowing the constraints or goals it’s hard to judge if this was a successful experiment or not. Did it provide meaningful information?
In short, what else do you need to know to properly interpret this data? Not just about the experiment or failures; what else do you need to know about the business, the technology or the customer use conditions?
It’s not a lot of data, post in the comments section how you would approach the analysis, your results that you would report, and what other information you would like to know given this experiment.
While not in the format of a CRE exam question, this simple example could become many different questions concerning data analysis, test design, management, etc.
Interested in an Upcoming CRE Preparation Course
Last January we ran a pilot version of a self-paced online CRE Preparation course.
A dozen people signed up and I’ve been gathering inputs, improvement ideas, and working to make the course as useful and effective as possible.
I’ll open the course again in June for registration for those preparing for the October exam date. If you would like to learn more about the course and details about when you can register, please visit the course page on Accendo Reliability. Sign up for the interested in the course list to get a few sneak peeks, more information and details about the course, and be the first to receive an invitation to joint the course.
Also, let me know what you are looking for in online courses not only for preparation or the CRE exam; also for your day to day work.
What do you want to know more about? What elements of reliability engineering do you struggle with that a course may help you master?
Related:
life testing question (article)
First 5 Questions (article)
Second 5 Questions (article)
You need to know everything involved on the design criteria, specifications (e.g. operating parameters, environmental conditions, functions, margins etc), use cases etc. Just about all information you can obtain.
Hi Michael, for the analysis of this test data, what is essential for you to create a meaningful report? Sure, it would be nice to know everything, yet what specifically do you need in this case? What questions would you ask, what information would you see, and why? cheers, Fred
First question, do the failures all have the same failure mechanism?
Good question – how would it change your analysis, Tim?
Group the problems with the same failure mechanism. Before analyse them.
Thanks Tim, grouping based on failure mechanisms is a good practice…. and helpful for fruitful data analysis. cheers, Fred