Field data Collection

[venkat]

Hi all,

I have been working on a research project .I was asked to do a field study which included instrumenting machines and also doing a survey to understand the customer needs and convert into engineering design requirements. For example if I have 50,000 machines in the field with an assumed average life of 1000 hrs / year for 5 years, Is there a way to determine statistical minimum number of machines that I have to monitor to get some confidence on different activities of those machines and also the number of months that i have to monitor each machine. How many responses do I need in this population if I do a survey. Please throw some light.Any suggestions and Ideas will be helpful.

Thanks

venky

[tarik]

It depends on what your objective is (prove a reliability goal, asses reliability ...). I recommend you start with these reading materials:

Demonstration Tests:
http://www.weibull.com/LifeDataWeb/test_design.htm

Using Simulation and for different censoring schemes:
http://www.weibull.com/freetools/discuss_simumatic.htm