[ce_seek]

Hi Robert. It’s been a long time since I opened this account. I just would like you to know you’ve been a great part of the whole journey. I finally graduated last year! Thanks for all the help! :D

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[ce_seek]

Hi Robert,

I was actually waiting for your response. Thank you very much! Yes, I actually removed the ctr point term in my equation. This is the resulting regression equation. However, I am not sure how the term for the ct. point would be of use.

Y= -0.144 + 0.3177 A + 0.1662 B – 0.04065 AB + 0.560 Ct Pt

I have also read in other post that when there is a curvature, you just remove the term for curvature in the equation. It just indicates that there is a curvilinear behavior.

Thank you.

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[ce_seek]

@rbutler

if the experiment is preliminary, which one is better to conduct?

1. two level factorial with center point replicates
2. go directly to three level factorial

Thank you!

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[ce_seek]

yes, you are right. i am going to validate the entire model, not just the center points. Thank you for your inputs!

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[ce_seek]

If I am going to replicate every thing, I will have 5 experimental runs right (multiplied by 3)?

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[ce_seek]

@rbutler

these are currently my objectives:

1. Investigate the main effects and interaction effect of (1st factor) and (2nd factor) on the response;
2. To obtain mathematical models that can predict the response through multiple linear regression analysis using (1st factor) and (2nd factor) as predictor variables;
3. To test model for curvilinear behaviour using centre point replicates

QUESTION 1: is this already okay?
QUESTION 2: Do i still need to validate my model using RMSE or R^2 method?

THANKS!

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[ce_seek]

hello! thanks for the reply. right now, im currently pursuing two level full factorial with centerpoint. and yes, my variables are continuous.

however, im not really sure of the process. is the model im gonna come up is still linear? and then ill just be doing a follow up check whether there is curvature? im thinking this is the sequence:

1. evaluate the main effects
2. evaluate the itneraction effects
3. come up with model (equation) using multiple linear regression
4. test for curvature?

does this make sense? or in the equation im gonna come up, there is a term belonging to the curvature part? not really sure. if you have reference material or examples, that would really be a great help!

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