How to create a survival curves (non-linear regression) using the linear-quadratic model?

JGru

I am completely new to JMP and I want to use the linear-quadratic model of cell death by radiation to fit my survival data (survival fraction) to the applied dose. 

The function is the following:  Y = exp(-1*(A*X + B*X^2))

Y = survival fraction 

X = (radiation) dose 

A = linear component represents cell death  due to a single lethal hit to the DNA

B = quadratic component represents cell death that only happens with two hits.

 

Does anyone have some insights or some advice? Thanks

 

MRB3855

Hi @JGru  and welcome. The easiest way way would be to linearize:

 

Y = exp(-1*(A*X + B*X^2)) is the same as:

• ln(Y)  = -1*(A*X+B*X^2)
• ln(1/Y) = A*X+B*X^2

So, if that is your model, you could use Fit Model and  make the sure the "No intercept" option is selected.

Just create a new column called Y2 (or any other name you like) and put the function Ln(1/Y) in that column. In Fit Model, put Y2 in as "Y", and X and X*X in as "Model Effects". 

Also, you will want to de-select "Center Polynomials" using the red triable next to Model Specification.