# ehh1.cf  Graphical test of distributional assumptions: exponential
 
nvar(
    dfile = ehc5.ple,           # data file 
 
    # select suitable range of time and survivor function 
 
    isel = gt(c3,0) & gt(c7,0) & lt(c7,1), 
 
    Time = c3,              # time axis 
    Surv = c7,              # survivor function 
    LogSurv = log(Surv),    # log of survivor function 
); 
lsreg = LogSurv,Time;       request OLS regression

psfile = ehh1.ps;  output file
psetup(
    pxlen =  80,    # length of x axis in mm
    pylen =  40,    # length of y axis in mm

    pxa   = 0,300,  # user coordinates on x axis
    pya   = -3,0,   # user coordinates on y axis
);
plxa (sc=60,ic=5);     plot x axis
plya (sc=1,ic=10);     plot y axis
plframe;               plot frame

plot = Time,LogSurv;
plotp = 0, -0.3527, 300, -2.6027;    plot regression line