Calculating average per hour for days

[Anonymous]

I have a set of data containing incoming calls for the past 3 months and I am attempting to create a line chart showing the incoming calls per hour for today as well as the average incoming calls per hour for the past 42 days. 

Here is where I am at...  I have a line chart with dimensions hour(inc_call_time) with a single expression of count(distinct(if(inc_call_time>=timestamp(today()),call_id)))

Now I am attempting to calculate the average for each hour of the day based on the past 42 days and I have had zero luck.  Is it possible with an expression if the date is not a dimension?

I can't access the community from the network I have the file in so I can't provide sample data.  I could probably fake something if someone really needs it.

Thanks.

[alexandros17]

Send me Data so I can help you ....

[Anonymous]

Ok, first time doing an inline table.  Let me know if this works for you.

I now want to add a line expression that shows a data point for average calls during that hour based on past days.

The below values aren't the same as in the data set but I tossed them together to help illustrate what I want to do.  Today, 2/15/2013, shows 78 calls at hour 8 and I want an average data point to show 66 calls (calculated from the table below excluding today and rounded down)

Date	Hour	Calls
2/5/2013	8	75
2/6/2013	8	74
2/7/2013	8	71
2/8/2013	8	60
2/9/2013	8	45
2/10/2013	8	62
2/11/2013	8	50
2/12/2013	8	70
2/13/2013	8	70
2/14/2013	8	92
2/15/2013	8	78