Wait analysis

If I have an instance that's under steady load from batch processes, is it valid to simply add up the wait times and divide by the number of processes to get average wait time?

For example, I have a statspack with the following:

            Snap Id     Snap Time      Sessions Curs/Sess Comment
            ------- ------------------ -------- --------- -------------------
Begin Snap:     244 17-Apr-02 15:41:43      144      11.5
  End Snap:     245 17-Apr-02 15:46:55      144      11.5
   Elapsed:                5.20 (mins)

[...snip...]

Top 5 Wait Events

~~~~~~~~~~~~~~~~~                                            Wait     % Total
Event                                               Waits  Time (s)   Wt Time
-------------------------------------------- ------------ ----------- -------
latch free                                        610,186      13,688   70.61
buffer busy waits                                  27,625       4,504   23.23
enqueue                                             1,084         776    4.00
db file sequential read                           156,662         356    1.84
log file parallel write                             6,564          42     .22
          -------------------------------------------------------------

I know that there were 96 concurrent connections from batch processes, and the other sessions were largely idle. Can I say that each one spent on average =>

(13688+4504+776+356+42)/(96*5.2*60)
= 64.7%

of wall time blocking on Oracle wait events?

-- 
Andrew Mobbs - http://www.chiark.greenend.org.uk/~andrewm/