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
- :
- 4PL fit (4 parameter logistic)

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

Dec 9, 2015 9:09 AM
(4234 views)

This may be a naïve question but I am confused about the 4PL equation used by jmp in curve fitting. I have a dataset of two variable and I choose: analyze>modeling>nonlinear

Then I plot the data and the red fit-curve button gives the option: Sigmoid curves>logistic curves>Fit logistic 4P

Now my question is; the equation used by jmp is f(x).

1 ACCEPTED SOLUTION

Accepted Solutions

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

Dec 11, 2015 11:06 AM
(6337 views)

Solution

Yes, the parameterization you give is different than the one used in JMP. The following is a reasonable discussion of the two parameterizations. JMP uses the one that it does to avoid having a parameter in an exponent, which makes estimation more difficult.

-Michael

Michael Crotty

Sr Statistical Writer

JMP Development

Sr Statistical Writer

JMP Development

6 REPLIES

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

Dec 9, 2015 9:17 AM
(3735 views)

It seems when I posted half my post was deleted??

...now my question is; the equation used by jmp is f(x)

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

Dec 9, 2015 2:10 PM
(3735 views)

Sorry you had trouble with your post. It seems though that there's still something missing.

Can you clarify your question?

-Jeff

-Jeff

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

Dec 9, 2015 5:24 PM
(3735 views)

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

Dec 11, 2015 11:06 AM
(6338 views)

Yes, the parameterization you give is different than the one used in JMP. The following is a reasonable discussion of the two parameterizations. JMP uses the one that it does to avoid having a parameter in an exponent, which makes estimation more difficult.

-Michael

Michael Crotty

Sr Statistical Writer

JMP Development

Sr Statistical Writer

JMP Development

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

Dec 10, 2015 3:35 AM
(3735 views)

Hello,

I looked through the Nonlinear Model Library and I found the the 4P logistic model you describe is called the Rodbard Model (4P) in JMP.

Best,

Bill

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

Dec 11, 2015 4:09 PM
(3735 views)