set xrange[0:120] set yrange[-1000:500] set key bottom lws2=2 p "response.dat_1" u 1:(-0.08617* ($4)/($3)*1000. ) w l ti "sc1" rep "response.dat_2" u 1:(-0.08617* ($4)/($3)*1000. ) w l ti "sc2" rep "response.dat_3" u 1:(-0.08617* ($4)/($3)*1000. ) w l ti "sc3" rep "