Was looking for the answer to this myself and found another option along the way..
The answer referring to naming the column was unclear to me when I read it..
From this beginner's view it was trying to say that when you select the whole row, in the drop down box in the upper left hand corner it says to the effect
A1:A1048576.. this you rename to give the column a name.. and use that in place of Excel's
This just kept causing me issues though, and like the way I found better, if it's applicable to whoever else finds this post's needs.
Instead, in say A1.. I have a title..
Total we'll say.. with all the values beneath it.
I just used that instead of renaming the column and worked basically the same without as many issues.. though in cases of Title characters that use functions such as
/ (which was an issue I was having) you need to remember to put apostrophes before and after ie..
'Km/Gal' confused Calc until I realized I needed them...
Had to name it something normal first
(kmgal) and then change it after I put in the formula to calculate the average.. In which Calc corrected it for me, and then I noticed what it did and fixed them myself.
So simply, in the use I used...