The first 25 percent

[Rum]

I have a multi-row, multi column spreadsheet. Of the columns, 3 of them are
the most crucial. Let's say,

Column A is: User

Column B is: Date

Column C is: Cycle Time (Calculated from B and another column)

What I would like to know is the average (median, etc...) Cycle Time for
the FIRST 25% (50%, 75% etc...) of the Users signed up.

Any ideas?

 

[Luke M]

If by "first 25" you literally mean the first 25% of the entries (or if you
meant by date, you could do a sort) a formula to use might be:

=AVERAGE(OFFSET($C$2,,,INT(0.25*COUNTA(A$2:A$100))))

Change the 0.25 to 0.5, 0.75, or 1 to calculate the other percentages.