Dear All,

I have used JMP to assess the effect of age at entry (AAE) and smoking status on a measure of mitochondrial function (continuous). Smoking status coded 1 or 0 (yes, no), using multiple regression.

I entered them all into fit model - Y = mitochondrial parameter, Construct model effects - AAE and smoking status, and run a standard least squares model. I noted that this output produced different parameter estimates to identical analysis using the same data on SPSS.

I then went back to JMP and performed the analysis but used the generalized regression option, and selected standard least squares as my estimation method. The output for this was then different to that from the original least squares analysis (with a different constant and different parameter estimates), and the SPSS model. The overall R2, adjusted R2 etc were all the same.

Whilst I believe if I entered an age and smoking status into any of the models it would give me the same estimate for the mitochondrial measure corrected for age and smoking status, I want to understand why the parameter estimates and constants are different for all three?

I have attached screenshots of the model outputs below.