Measure for Average

Hello

Maybe you can help. I have tried Quick Measures  and other DAX Measures, but I'm not getting result I want.

I have a table and I would like to find the average of how many start time of calls in a period. I have created column in the table that shows if the start time is 12:15 it will fall into the group 12-13. I can find the total amount of time per period in that day, but I would like to see the average.

The Graph I am using looks like this

            Mon   Tue   Wed   Thu  Fri   Sat   Sun

00-01

01-02

02-03

03-04

I would like to drop the measure in here and show the average count of the start times in those periods on those days. 

Thanking you in adavnce