Average Weekly Data

[shmoowalker]

I work for a 5k organization and we handle thousands of registrations. I want to be able to average the week to week registrations more easily. Right now I have been taking the difference from week to week (i.e. (Day 7 - Day 1) + (Day 14 - Day 7) + (Day 21 - Day 14) etc.) and dividing it by the count of weeks using counta. Is there an easier way to sum the difference of every 7 days and average them out?

[Hurricanefly]

Could you not use =Average? If not it may be better to attach a sample workbook