Monthly average

[bobby769]

Hello everyone,

This is my first post.

I need to find a monthly average.

The data is as follows:
Start_date End_date Duration

1/7/2011	1/15/2011	8
2/9/11	4/22/2011	72
3/16/2011	4/15/2011	30
4/5/11	4/28/2011	23
4/8/2011	5/1/2011	23
5/5/11	5/7/2011	2
6/30/11	7/15/2011	15
7/1/11	8/22/2011	52
7/7/2011	8/2/2011	26
7/13/11	7/25/2011	12
7/13/2011	2/13/2012	215
7/22/11	9/20/2011	60
7/22/11	9/22/2011	62
7/25/11	9/19/2011	56
8/31/11	10/4/2011	34

<colgroup><col><col><col></colgroup><tbody>
</tbody>

The Duration is the difference between the end and start date, or the amount of days it takes to go from start to end.

Now I need to find the average duration for each month.
Column D looks like this:
2011
Jan
Feb
.
.
.
2012
Jan
Feb
.
.

Column E is the output column

Thanks in advance.

 

[Oeldere]

This question is solved on another forum.