Fractile with Calculated Field??

[#1]

Hey guys, I have a question around using fractiles with calculated fields.  I want to do fractile(NumberofPurchases,.25) but that does not work and neither does fractile(count(distinct(purchases)),.25).  Help?

Customer Name	NumberofPurchases
	count(distinct(purchases))
Name 1	50
Name 2	25
Name 3	15
Name 4	2
Name 5	8

[rwunderlich · Accepted solution]

It seems a bit illogical (in QV terms) the way you've stated it. Count(distinct purchases) is a single value for each row. A single value can't have a fractile.

Do you want the fractile of the 5 aggregated line values (50,25,15,2,8)? If so, try

=fractile(TOTAL aggr(count(DISTINCT purchases),[Customer Name]),.25)

-Rob

[#3]

Thank you - this wasn't just the right answer, it was the perfect answer. 

[#4]

Please help me.

I have exam data of a class of 50 students.

Now I want to calculate the average (and, median) of top 80% students of that class.

How can I do that?
Please help.

Thanks.