I have the following data below with pre-treatment data (denoted with the negative times) and post-treatment data (denoted with the positive times). I would like to graph this two-way to create a %predicted value of MT which are already percent values. I am trying to graph it similar to figure 2 in this publication (https://pubmed.ncbi.nlm.nih.gov/27816444/). However, I get a straight line in my graph when I use the codes below.


Array

Code:
mixed MT c.time || id:, covariance(unstructured) nolrtest nolog
quietly margins , at(time = (-5(1)5))
marginsplot , title("") plotopts(msymbol(none) lcolor(black)) ytitle(BP (%)) ylabel( , angle(horizontal) nogrid) xtitle(months) level(50) recastci(rline) ciopts(lcolor(black) lpattern(dash)) xline(0)
end

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input byte(id time) int MT
 1  -5 110
 1  -2 116
 1   1 189
 2  -3 135
 2  -1 170
 2   1 106
 2   2 155
 8  -4 149
 8  -1 169
 8   1 160
11 -10 170
11  -1 180
11   1 144
14  -5 174
14  -1 149
14   1 145
14   2 133
14   5 100
end