topic Re: How to populate additional column with a quantile value in Discussions

How to populate additional column with a quantile value

sfkeydel — Thu, 16 Sep 2010 17:26:46 GMT

Hello,

Is there a simple column formula that will populate the quantile of a value in a different column?

For example:

I have a column with the following values [1,2,3,4,5,6,7,8,9,10]. I would like to create a new column that will simply hold the quantile value of each of the values in my original column.

I tried the quantile function in the Column Properties dialogue, but that doesn't seem to be the answer (or I'm using it incorrectly).

Thanks

Re: How to populate additional column with a quantile value

XanGregg — Wed, 22 Sep 2010 13:28:21 GMT

JMP's Quantile functions work the other way around: given a quantile value they produce a data value. If you plot the quantile function (script below), you'll see it has flat spots, which makes it hard to define the inverse function that you want.

You can get close with (Col Rank( : x ) - 1) / (N Row() - 1), but ties are arbitrarily ordered.

The Ranking Tie() function will average ties together, but requires more set-up since it's not a "Col" function.

Re: How to populate additional column with a quantile value

sfkeydel — Thu, 23 Sep 2010 13:00:51 GMT

Xan,

Much appreciated. I'll experiment with this. One of my colleagues suggested a workaround which, as it happens, is good enough for what I'm trying to do:

If(:Callback % >= Col Quantile(:Callback %, 0.75), "Upper", "Normal")

Thanks again!

Stefan