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marjolein

Community Trekker

Joined:

Dec 30, 2014

How do I create a model with a defined profile as a factor?

Hi all,

 

I have a question regarding DoE design. 

 

Normally, I use continuous factors with fixed values for 0, -1, +1, with the custom design DoE. However, I now have to create a model for a cell culture process (duration is multiple days), where one of the input factors has a profile at the lower range (the other factors will be fixed values for 0, -1, +1). Can someone explain to me how I can design this model? 

 

further more, what would be preferred, from a statistical point of view: 

1) keep upper range fixed and centerpoint fixed, so only profile for lower range

or

2) have same shape profile for upper range and centerpoint as used for -1

 

I have plotted scenenario 1 and 2 in the attached file as I cannot add the pictures in this message. 

 

any help is very welcome, I very much look forward to your response/ideas

 

kind regards,

Marjolein

 

 

1 ACCEPTED SOLUTION

Accepted Solutions
Andrea_

Not applicable

Joined:

Oct 28, 2018

Solution

Re: How do I create a model with a defined profile as a factor?

Hi Marjolein,

yes, the categorical factor wouldn't follow a profile, but it doesn't have to. Just create a categorical factor with three levels:

Factor NameRoleValues  
XCategoricalL1 = profile 1L2 = profile 2L3 = profile 3

 

The profiles don't have to be the same, each can follow an unique time-program. The "mid-level" (profile 2) doesn't have to be the "center-point" as you showed in your Word-file in figure 2. You can take the profiles as in figure 1.

Regards,

Andrea

3 REPLIES 3
Andrea_

Not applicable

Joined:

Oct 28, 2018

Re: How do I create a model with a defined profile as a factor?

Hello Marjolein,

as far as I know, there is no preferred profile from the "statistical point of view". You have a categoric factor which is the profile. The question is: Which version does make more sense for the cell culture process and the purpose of your experiment?

Regards,
Andrea

marjolein

Community Trekker

Joined:

Dec 30, 2014

Re: How do I create a model with a defined profile as a factor?

Hi Andrea,

 

Thanks for your reply! 

Can you explain a bit further how you would apply categorical variables to make the profile in time? I assumed that the levels for the categorical factors will be same value throughout process time, so its then not creating a profile over time.

 

kind regards, Marjolein

Andrea_

Not applicable

Joined:

Oct 28, 2018

Solution

Re: How do I create a model with a defined profile as a factor?

Hi Marjolein,

yes, the categorical factor wouldn't follow a profile, but it doesn't have to. Just create a categorical factor with three levels:

Factor NameRoleValues  
XCategoricalL1 = profile 1L2 = profile 2L3 = profile 3

 

The profiles don't have to be the same, each can follow an unique time-program. The "mid-level" (profile 2) doesn't have to be the "center-point" as you showed in your Word-file in figure 2. You can take the profiles as in figure 1.

Regards,

Andrea