Taking Average from specific data of a dataset

Data= 0.11,( -1.11, -0.75), -0.02, -0.36, (-0.97), -0.35, (-1.02, -1.33, -1.00), -0.15, (-0.66, -0.59, -1.21, -0.70), 0.06, (-1.65), 0.03, 0.25, (-1.35), -0.08,(-0.91, -0.82, -1.29), -0.26

In this data set 7 events have values less than -0.5. ( ) indicate one event, this is for better understanding, don't have in real data. My purpose is to take average of each event > sum all of this average > again divide this sum by total number of events (i.e.7).

This process will repeat for 40 data set. Thanks in advance for your help.

Badrul