How to average the last seven values in a column? - google-sheets

Question

I am trying to find the average of the seven most recent entries in a row, as seen in
this
spreadsheet.
I found a few questions similar to mine, but I am still pretty confused on how the answers work. The questions similar to mine can be found on the left side of my spreadsheet.
I think that the formulas would work for me with a few simple adjustments of which values to use, but I can't seem to figure it out. I would really appreciate if someone could explain one of the existing answers or come up with another one that works.
The spreadsheet is updated daily, so I need something that would continue to work as more and more data is added to the column.

Answer 1

Try:
=round(AVERAGE(OFFSET(H1,MAX(ARRAYFORMULA(ROW(H:H)*--(H:H<>"")))-7,,7)))
here's working sample
Explanation
We are getting the last non empty row: MAX(ARRAYFORMULA(ROW(H:H)*--(H:H<>"")))
Then with offset formula we are getting the range of last 7 cells in a column.
And then just use AVERAGE.
More info
You may find more info about finding the last non empty row here:
Selecting the last value of a column

Answer 2

Another way is to use INDEX and MATCH. The first match finds the position of the last number in the range and takes 6 away from it: the second match finds the position of the last number in the range. Passing it through the INDEX function gives a reference that you can use to give a range of 7 cells for AVERAGE to work on.
=average(index(H:H,match(999,H:H)-6):index(H:H,match(999,H:H)))
So my answer is like your Link2
The big snag here is if you have a text cell in the range (like "Nothing") it is much more difficult to work out which cell to start from to get an average of 7 cells. I think I know how to do it in Excel using OFFSET but offset doesn't seem to work in the same way in Google Sheets.
However I can see there is a solution to this in your Link3 which should work for you if you change A:A to H:H and SUM to AVERAGE. I have tested it on the average of the last ten cells which includes a "Nothing" cell:
=ArrayFormula(AVERAGE(QUERY(SORT(H:H,ROW(H:H)*ISNUMBER(H:H),0),"select * limit 10")))
and it gives the correct answer 61.8.
The way array formulas work in general is that instead of passing a single value to a function you pass a whole range or array (a list of values) and the function processes them one by one. The above formula takes the whole column H:H and sorts it on the row numbers in descending order but those cells which don't contain a number give zero in the multiplication and are sorted to the bottom. Then the query takes the top (in my case) 10 cells and passes them to AVERAGE.
BTW this doesn't have to be declared as an array formula: this also works
=AVERAGE(QUERY(SORT(H:H,ROW(H:H)*ISNUMBER(H:H),0),"select * limit 10"))