reset

set title "Hallwiderstand bei konstantem Magnetfeld B = 1.0 T"
set xlabel "[I_s in A]"
set ylabel "[U_r in V]"
set grid xtics ytics
set key top left

f(x) = a*x + b
fit f(x) 'DatenHallInAsBconst.txt' us ($1):($3) via a,b

plot \
'DatenHallInAsBconst.txt' us ($1):($3) notitle lt 1, \
f(x) title "Ausgleichsgerade" lt 3

set output "hallwiderstandinasbconst.eps"
set term postscript enhanced eps color; replot