turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- JMP User Community
- :
- Discussions
- :
- Peak Prediction

Topic Options

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Jun 6, 2012 8:48 AM
(569 views)

Hi,

I need a ton of help solve this problem. I have a distribution (blue) that is made of two components. I know a distribution of the first component (red) but not the second. Is there any ways to predict or estimate the distribution of the second component ?

Thanks in advance.

4 REPLIES

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Jun 6, 2012 12:11 PM
(468 views)

The first component looks left censored. Check procedure FMM for finite mixture models estimation.

PG

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Jun 7, 2012 9:36 AM
(468 views)

PG,

Thanks for a suggestion. I tried FMM but it was not sensitive enough to predict two distinctive distributions even though I manually played with some parameters.

Aki

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Jun 7, 2012 10:23 AM
(468 views)

Seems like you have only one parameter to estimate in this problem : the proportion represented by the first component in your distribution. Given a proportion, the shape ofthe second component can be found by subtraction. But then, what would like to optimize? Do you have a hypothesis about the shape of the second component? Is it supposed to be the same as the first component? Is it supposed to be normally distributed?

PG

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Get Direct Link
- Email to a Friend
- Report Inappropriate Content

Jun 8, 2012 10:09 AM
(468 views)

I can use subtraction to guesstimate the distribution of the second but I don't know if subtraction gives me the accurate estimate of the second component. I am assuming that a second distribution is near normal although I have no concrete evidence for that, and a proportion of the first distribution shown in a previous graph is misleading. It is actually an overly graph of the suspected first component (red) and the distribution in question with proportions being normalized (y-axis).

Anyway, what I was really hoping was that JMP had some functions that help me to build a model for two component normal mixture, by which I could pick the best overall distribution that would resemble the mixed distribution in question. Maybe what I need is FMM or EM scripts ?