I have two columns of data. One is the date time when the X number if items finished. Two is the number. I want to sum the amount over 20 minute time intervals and plot the sum of the interval versus ending date/time.

So for the data example below I would have point (10/17/07 09:20, 25) to plot.

Date/Time Amount
10/17/07 09:00 8
10/17/07 09:03 1
10/17/07 09:10 13
10/17/07 09:17 3
etc...