/* logistic.sas */ TITLE1 'Plots of the Logistic Function'; /* Generate the data for different logistic functions */ DATA data1; beta3=1; DO beta1= 0.5, 1; DO beta2=0.1, 1; DO t=-10 TO 10 BY 0.5; s = COMPRESS('(' || beta1 || ',' || beta2 || ',' || beta3 || ')'); f_log=beta3/(1+beta2*EXP(-beta1*t)); OUTPUT; END; END; END; /* Graphical Options */ SYMBOL1 C=GREEN V=NONE I=JOIN L=1; SYMBOL2 C=GREEN V=NONE I=JOIN L=2; SYMBOL3 C=GREEN V=NONE I=JOIN L=3; SYMBOL4 C=GREEN V=NONE I=JOIN L=33; AXIS1 LABEL=(H=2 'f' H=1 'log' H=2 '(t)'); AXIS2 LABEL=('t'); LEGEND1 LABEL=(F=CGREEK H=2 '(b' H=1 '1' H=2 ', b' H=1 '2' H=2 ',b' H=1 '3' H=2 ')='); /*Plot the functions */ PROC GPLOT DATA=data1; PLOT f_log*t=s / VAXIS=AXIS1 HAXIS=AXIS2 LEGEND=LEGEND1; RUN; QUIT;