Problem 6 You\'re a manufacturing engineer for a producer of oil field equipment
ID: 3071661 • Letter: P
Question
Problem 6 You're a manufacturing engineer for a producer of oil field equipment, and you're investigating the effectiveness of two coatings on iron pipes. You have 30 pipes of all the same characteristics and quality. For 10 each, you apply coating A, coating B, and no coating. Once treated, the pipes are buried in soil for a year, removed, and the depths of the corrosion pits measured, with the deepest pits recorded below. Your measure is obviously "depth of deepest pit." Why is that measure a good one to help your investigation? What might be wrong with such a measure? (or what does it a. not effectively address?) b. Analyze with 95% confidence, what decision do you make? By hand. Test assumptions. 47 41 43 41 32 24 43 53 52 A 51 B 73 43 47 53 5847 53 38 61 56 59 52 63 65 50 62 48 58 Untreated 81Explanation / Answer
a.
Depth of deepest pit is a good measure for investigation as the pipes will be connected in series and even is the single pipe gets damaged or leaked due to corrosion, rusting or any other reason, the complete oil pipe line and sustem will go non functional, even if all other pipes are working fine. If an other depth like 95% depth or mean depth is used for investigation, it would have a high risk of faliure of complete pipe line as even if single pipeline got damages due to this,, the complete system will fail thus, depth of deepest pit is a good measure for investigation.
however, if due to some reason or human error the coating on a particular pipe is not proper, then the depth of deepest pit on not properly treated pipe will be more due to human error and not due to efficiency of coating. for example the depth of deepest pit with coating B is 73, and depth of second deepest pit with coating B is 61 and there is a large difference in both the values. Therefore it could be possible that there was some inefficiency in applying coating on that particular pipe which is leading its way for higher depth of pit.
Thus for ensuing the depth of deepest pit as a measure of investigation, it should be properly checked and monitored that coating on each pipe is applied properly and shoud be as per standard coating procedure.
b.
as seen from the CI, 95% of values of pipe coated with A falls between 37 to 48
as seen from the CI, 95% of values of pipe coated with B falls between 47 to 59
as seen from the CI, 95% of values of untreated pipe falls between 53 to 65
depth of deepest pit A 51 41 43 41 47 32 24 43 53 52 53 B 73 43 47 53 58 47 53 38 61 56 73 Untrated 81 52 55 63 65 50 62 48 58 59 81