Mixture design with constants

[#1]

Hello Community,

I have a short question concerning the use of mixture designs with 6 ingredients varying and 2 ingredients fixed constant:

I forgot to set the sum of the mixture to less than 1 ( Mixture % = 1 - constant 1 - constant 2). So right now when I sum all my ingredients, it makes slightly higher than 1. 

I already did all the modeling in this way and realized this just after. If I set the sum of the mixture components (without the constants) to the real percent of the total (not 1, but aroun 0.98). Could this change in any way the modeling results?

I personally do not think this will impact the modelling as such, but it will certanily impact the percent of the ingredients for the total recipe.

What do you think ? 

Sorry for not sharing data for no. It's confidential.

[#2]

Hi @Julianveda ,

Yes, as you already said. I think, removing the constants from mixture design and reducing the total mixture sum will not affect the modelling. But then as you said you have sum of mixture higher than 1. I think if you normalize the whole mixture values, the % of contribution of each ingredient should be the same even if the sum of mixture is 0.98 or 1 or 1.02.

I hope this answer is correct.  And I hope its not too later for you to make a new design with correct mixture sum.