set terminal png
set output "linearita.png"
f(x)=k*x + q
fit f(x) "mereni_rozsahu.txt" using 1:2 via k, q
plot "mereni_rozsahu.txt" using 1:2 with points, f(x)
set terminal png
set output "linearita.png"
f(x)=k*x + q
fit f(x) "mereni_rozsahu.txt" using 1:2 via k, q
plot "mereni_rozsahu.txt" using 1:2 with points, f(x)