d1 = [7.743 7.479 7.596];

d2 = [5.54 5.70 5.49];

d3 = [12.14 12.14 12.14];



data = [2 mean(d1) sqrt(var(d1));

        10 mean(d2) sqrt(var(d2));

        40 mean(d3) sqrt(var(d3))];



errorbar(data(:,1),data(:,2),data(:,3),'o','Markersize',10);

xlabel('Frequency in MHz');

ylabel('Attenuation (in 100ft) in dBm');

title('Frequency dependent attenuation in RG58 cable');

grid on;