I have the following column data:

Column A: Location Names
Column B: Category Codes of the locations (i.e. "A - G")
Column C: Page Volume counts (i.e. 45,000)
Column D: To be populated by results from #3 below

I want to investigate any ideas YOU have that could help do the following:
  1. Calculate the "mean", or "Average" of all the page volume counts for all locations in each specific category code (i.e. the average for all "C" locations)
  2. Determine the Standard Deviation for each category (i.e. the standard deviation for the "A" group, "B" group, etc)
  3. Finally, I need to place in Column "D" next to each location an indicator ("+", "-" or "OK") showing if that location's Page Volume is either higher than, lower than, or inside of the standard deviation range for the category.
Thanks in advance for your ideas!