I need to show that my predicted data in +or- something in error range when I vary the predicted data with experimental data.But in excel it is not easy .KIndly help. I need to lead in step by step manner.
You might try gnuplot (free opensource software), which offers different kinds of plots from files with tabular data (an export as .csv separated by spaces from Excel) and of functions given by a formula within one plot.
Another possibility would be one of the computer algebra programs like Maple or Mathematica - these are not free software but your university might have paid licenses.
In fact it's easy in Excel. Create a Table that contains the experimental data, predicted values and errors (Upper and Lower Borders). Then select all of them and in Insert Manu on the ribbon select Line chart. After that, every time you change your data in the Source Table the Chart will be updated automatically by Excel. I hope this help, if you have further questions just ask.