I'm a newbie at CR 7 (sorry if I'm not following etiquette or this has been posted before). I've been given a pre-existing CR file to edit. Basically what I need to do is:
a) retrieve data for 'year' and 'year-1' (done)
b) based on retrieved data: if 'sales_value_for_month' > 500, include it in the dataset to calculate summaries
c) need the following summaries:
    1) sum of 12 months of data for both 'year' and 'year-1' as summary
    2) average of 12 months of data where average=(sum of monthly values>500)/# of months with values>500

I've tried the sum and avg functions but I'm not getting the data I need and I don't know enough about how to create custom formulae to sort this out.

Any help/guidance is appreciated.

IIRC, running total weren't available in CR7.  :(