Usually the best approach to this is to calculate your graph points as data accumulates and to then store that into a Stream and plot your graph from that stream.
Other wise the info table functions and javascript can certainly help you calculate the points you need from a raw data set but it will be much more process intensive and therefor slower to render. so a 'running' aggregate calculation that is stored as data accumulates would work better.
Not sure if that is possible in your use case though.
