reset

set encoding iso_8859_1
set title "1/a über R"
set xlabel "[R in {/Symbol W}]"
set ylabel "[1/a in 1/m]"
set grid xtics ytics
set key top left

f(x) = a*x + b
fit f(x) 'Daten22offen.txt' us ($1 * 49.8):(1/($2)) via a,b

g(x) = c*x + d
fit g(x) 'Daten22geschlossen.txt' us ($1 * 49.8):(1/($2)) via c,d

plot 'Daten22offen.txt' us ($1 * 49.8):(1/($2)) title 'Messwerte (offene Brücke)' lt 1, \
     f(x) title 'Ausgleichsgerade (offene Brücke)' lt 1, \
     'Daten22geschlossen.txt' us ($1 * 49.8):(1/($2)) title 'Messwerte (geschlossene Brücke)' lt 3, \
     g(x) title 'Ausgleichsgerade (geschlossene Brücke)' lt 3

set output "22.eps"
set term postscript enhanced eps color; replot