Greetings Stata Users & experts,

I'm currently reviewing some of the methods to graph relationships between variables. I have found the twoway lfitci, qfitci and fpfitci as really useful commands. However, I'm kind of struggling how to get the actual functions estimated and used for predictions. For example. I'm using this command to generate some variables:


Code:
clear all
 
set obs 100
gen n=_n
 
set seed 1234
 
gen x=rnormal()
gen x_sq=x*x
gen z=rnormal()
gen y= 1 + (0.5*x)+ (- 0.2*x_sq) + (1.5*z)

And then I'm using fpfitci to get this result:

Code:
twoway (fpfitci y x)

And getting some interesting fit of my data. However, I cannot observe anywhere what kind of functional form has been done to reach this fit, and the parameters used. Is there any way to display the functional form used to compute this adjustment?.


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