I'm using a predefinied program... but I don't know because give me this error:
Clear["Global`*"]
Remove["Global`*"]
<< "ErrorBarPlots`"
xdata = {180, 200, 220, 240, 260, 280, 300, 320, 340, 360}
{180, 200, 220, 240, 260, 280, 300, 320, 340, 360}
ax = First[xdata]
180...