How to condense several rows into fewer rows?

[gavin_machine]

Hello,

Is there a way to condense several rows of data into a smaller number of rows?

For example: Say I have 10 rows of data:

10
8
90
7
6
78
3
4
5
55

And I want to condense them in to five rows, perhaps based on an average of every "n" rows or etc... Is there a way to do this in excel, or any type of algorithm that anyone can suggest?

If I average every two rows based on the above 10, then the condensed result would be:

9
48.5
84
3.5
30

In addition, is there a way to do this if I am dealing with numbers of rows that are not divisible by each other (for example if I want to condense the above 10 rows into 4, then I would have to average every 2.5 rows)?

Thanks a lot!