Hi William,
In order to get those calculations for the average across all of your records instead of getting a total of all the averages for each individual records you actually need to create a summary/statistics table and use a relationship to bring up both of those numbers as a summary field in order to do math on the total values. In your instance you would need a table along the lines of Monthly Ticket Types with records that contain a text field set up for each possible combo you want to report off like:
Monthly Combo Field:
January-2019-Landscape
January-2019-Maintenance
January-2019-Misc
February-2019-Landscape
February-2019-Maintenance
February-2019-Misc
March-2019-Landscape
March-2019-Maintenance
March-2019-Misc
Then you would want that tables key field to be set to the Monthly Combo field you created and you have filled it with records to match what you want to report off of you are ready to add a formula field in your Tickets table called something like Monthly Combo Formula, and fill it with a formula that will take the date, the year, and the ticket type and put them together in a format like the records that exist on your Monthly Ticket Types table. That should fill each record in with its matching Monthly Ticket Type record. Then you can create a relationship between the two tables where Monthly Ticket Types have many Tickets and the related record field is your Monthly Combo formula.
Then once it looks like everything is set up correctly when you look at records and they seem to be correctly related you want to go into Monthly Combo formula then save your formula before setting the field to be just a plain text field instead of a formula. Once you do that your records are related and you can then go into your relationship between Tickets and Monthly Ticket Types and you can add summary fields to summarize the number of open tickets and closed tickets. Then once you have that set up you would go back into Monthly Combo and turn it back into a formula field and make sure your formula is still in there. Then any new records added will link up so long as there is a matching record added into the summary table. Then at that point to maintain your summary table you just need to make sure you add records for every combo you want to track, that usually means once a month adding a record for each type that month.
Once this is all set up then you can make formula fields on your Monthly Ticket Type table and do the math right off of your summary fields. If in the future you ever need to add new summary fields you would just do the same step of making the field a text field, add the summary field, and then turn it back into the formula. This is definitely a more advanced technique and can take some maintenance but it is the way to get to a summary calculation like that. I hope this information is helpful.
