Average of fourth quartile

[kennethand]

How do I find the average of the fourth quartile?

I can find the fourth quartile point using this expression: Fractile(Q21Num, 0.75).

But how do I get average of the values belonging to the fourth quartile ?

[TKendrick20]

You could try this. Though to make sure you're getting the value you're expecting you may want to so some analysis in Excel as well.

=IF([ValueField]<Fractile([ValueField],0.75),AVG([ValueField]))

[sunny_talwar]

What all are your dimensions where you find the Avg?

Avg(Aggr(Fractile(Q21Num, 0.75), SomeDimensionsHere))

[kennethand]

I've actually tried this before posting without any luck. Have you tested it yourself ?

[kennethand]

"What all are your dimensions where you find the Avg?"

What do you mean? I'm not sure ...

[sunny_talwar]

You must be calculating your Fractile over a dimension right?

Dim, Fractile

A, 10

b, 20

c, 30

and now you want to find the average? What is this Dim over which you want to calculate the Average?

[TKendrick20]

I guess you need to define a variable to get it to work.

Variable (called vFractile):

Fractile([ValueField],0.75)

Expression:

AVG({$<[ValueField]={'<$(=vFractile)'}>} [ValueField])

[kennethand]

Hmm  - for some reason it's not working for me.

I've have a small testsample looking like this:

RespID	Q21Num
1	10
2	20
3	30
4	40
5	50
6	60
7	70
8	80
9	90
10	100

Using this expression: Fractile(Q21Num, 0.75) I get the value 77.5 as the fourth quartile. So far so good. Then I like to measure the average of the fourth quartile - in other words I need to calculate the average of every value higher than my fourth quartile point (77.5):

Average of 80 + 90 + 100 = 90

Please take a look at my qvf file.

[marcus_sommer]

Maybe this is helpful in any way: statistical aggregations - parts between frac 0.1 and 0.9.

- Marcus

[sunny_talwar · Accepted solution]

Try this

AVG({$<[Q21Num] = {">=$(=vFractile)"}>} [Q21Num])

With your variable using an equal sign

=Fractile(Q21Num, 0.75)