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View Full Version : 3 sets of Data. Possible to acquire the 4th with MINITAB?


joonyeen
10th August 2006, 09:14 AM
Hi there everyone in the cove!!!

My first ever visit and hoping for many more to come. I have come to the usage of this programme (minitab) 2 weeks ago and found that my knowledge is really limited. I am currently a uni Student and am trying to interpret results for the tribology department.

I am currently working on datas from this experiment :

Machine - Optimol SRV III

Variables
- Temperature (-40, 25, 100, 200, 250)
- Lubrication ( A, B)
- material of the metal piece (C, D)

In this experiment, the ceramic sphere is sitting on a metal piece. It is then acted on by a constant force and oscillates horizontally with a constant amplitude, different lubrication, and also in different temperature. The resulted calotte on the sphere is then measured in mm.

My professor has given me 3 sets of datas:
1 - A and C
2 - A and D
3 - B and C

with the help of MINITAB, i have plot graphs and can make assumptions on the difference between these 3 combinations.

the question now is, am i able to use MINITAB to come out with the 4th set of data which is the usage of the combination of B and D
hereby i thank you in advance if any one of you could help me in this. thank you very much!!!!

ezorangee
10th August 2006, 11:34 AM
I need some more information....Are you doing a designed experiment with three factors....Temperature, Lubrication, and Material? Is the data the professor gave you the responses for this experiment? I'm sorry for my confusion, but I am not sure what you mean by aquiring the 4th data set.

Regards

Tim Folkerts
10th August 2006, 12:01 PM
If I understand correctly, you are trying to predict what would happen if you ran the experiment with B & D, but that combination has not actually been tried.

If you assume linear relationships and no interactions for lubrication and material, then you could come up with a prediction for the combination B & D.

Experiments 1 & 2 hold A constant, so you could compare the effects of C vs D.
Experiments 1 & 3 hold C constant, so you could compare the effects of A vs B.Once you know the effect of A vs B and the effect of C vs D, you could predict the results if you tried B & D

For example, suppose the results were

Experiment 1 (A&C): 10 mm
Experiment 2 (A&D): 12 mm
Experiment 3 (B&C): 13 mmGoing from C to D increases the result by 2 mm, so you could increase the result of Experiment 3 by 2 mm to predict 15 mm for B&D. (Or going from A to B increases the result by 3 mm, so you could increase the result of Experiment 2 by 3 mm to again predict 15 mm for B&D.)

Of course, this makes some pretty major assumptions about linearity and lack of interaction. If this is not true, or if random variations are a significant factor, then the predictions may be no good at all.


Tim F

joonyeen
10th August 2006, 12:21 PM
hi there,

the data given are the responses from the experiment which i have carried out. It is indeed an experiment with 3 variables.

i am trying to predict the result for the combination of B and D. i might or might not be doing the experiment base on these 2 variables, but i was asked to find out what the outcome will be, or what the assumption will be. In a way, it will help in saving cost and time when carrying out further experiments in the sense that if something that we assume has no result, we will not waste time and effort in continuing doing so.

thanks ...


I need some more information....Are you doing a designed experiment with three factors....Temperature, Lubrication, and Material? Is the data the professor gave you the responses for this experiment? I'm sorry for my confusion, but I am not sure what you mean by aquiring the 4th data set.

Regards