TCanvas c;
c.SetGrid();

.! curl https://raw.githubusercontent.com/root-mirror/training/master/2016/macro2_input_expected.txt -o macro2_input_expected.txt

TGraphErrors graph_expected("./macro2_input_expected.txt", "%lg %lg %lg");

graph_expected.SetTitle(
    "Measurement XYZ and Expectation;"
    "lenght [cm];"
    "Arb.Units");
graph_expected.SetFillColor(kYellow);
graph_expected.Draw("E3AL"); // E3 draws the band

TGraphErrors graph("../macro2_input.txt", "%lg %lg %lg");

graph.SetMarkerStyle(kCircle);
graph.SetFillColor(0);
graph.Draw("PESame");

TLegend leg(.1, .7, .3, .9, "Lab. Lesson 2");
leg.SetFillColor(0);
leg.AddEntry(&graph_expected, "Expected Points");
leg.AddEntry(&graph, "Measured Points");
leg.Draw("Same");

%jsroot on
c.Draw();

graph.Print();