Calculating the average time between tasks

MicheleOdell 

Write one of the following (whichever you understand best) to convert text to numeric time:

=--TEXT(O3-N3,"[h]:m:s")

or

=1*TEXT(O3-N3,"[h]:m:s")

or

=VALUE(TEXT(O3-N3,"[h]:m:s"))

Format the cells as Custom [h]:mm:ss .

Note that I use [h] instead of just h.  That allows for the possibility that time exceeds or equals 24 hours.

And note that I use VALUE, not TIMEVALUE.  Again, that allows for the possibility that time exceeds or equals 24.

Even if you know the possibility does not exist for your current data, it is a good habit to get into, and there is no harm in always doing it.

Also, format the AVERAGE cells as Custom [h]:mm:ss .  But you might consider [h]:mm:ss.000 , since the average might include fractional seconds.