How to manipulate chart base data

I have a list of developer development time in hours that I’m summing by week. I need to average these totals by dividing each total by 6. See below.

Week Total Hours
2/1/2015 200 / 6 = 33.3
2/8/2015 250 / 6 = 41.6
2/15/2015 192 / 6 = 32.0

I can graph the sums very easily, and the average function doesn’t work because I need a fixed dividend. Help!

Hi,
The easiest way here is to create a calculated field with the formula like [WeekHours] / 6 and use this field in your chart.

That works!!! Thanks.