first you draw another column and then from the grouped data you write the midpoints then you plot the frequency, and make sure also you are plotting the mid points for example:
frequency
0<10 6
you would plot 5 in the x axis and 6 in the y axis
By its very nature, measuring cumulative frequency on either axis of a graph will produce a continuing line on the opposite axis. Therefore, it is impossible to construct a closed frequency polygon...
this video is very informative on drawing cumulative frequency curves on the microsoft excel (applicable to all versions): www.youtube.com/watch?v=gTXfS03u6GE
Draw your plan with your variables (forgive the approximative vocabulary, I'm not native) on the X axis, and with the cumuled frequencies on the Y axis. (exemple: A0.1; B.0.12, C==0.6 etc will imply...