Understanding Count of Calls

[Ashmita.Thapar]

I want to gain some understanding of how number of total calls in any application works.

Stall count is basically a part of some slow/very slow transactions which have crossed average threshold by a higher extent.

So, which of the following is true?

1. Number of total calls = Number of normal + slow +very slow + error + stall 

   OR

2. Number of total calls = Number of normal + slow + very slow + error

Thanks