How to specify raw polynomials in Spotfire's Linear Regression feature?
Article ID: KB0078879
Updated On:
| Products | Versions |
|---|---|
| Spotfire Analyst | All supported versions |
| Spotfire Enterprise Runtime for R | All supported versions |
Description
How to specify use of raw polynomials (instead of orthogonal polynomials) in Spotfire's Linear Regression feature?
Issue/Introduction
How to specify raw polynomials in Spotfire's Linear Regression feature?
Environment
All supported environments
Resolution
A Spotfire user of the "Tools > Linear Regression..." feature who wants 'poly()' coefficients that correspond directly to the x, x^2, x^3, etc. model components needs to specify 'poly(.., raw = TRUE )' in the formula the user provides in the Regression dialog's Formula field, using syntax like this:
poly(`X1`, degree = 2, raw = TRUE)
in place of this:
poly(`X1`, degree = 2)
There is no point-and-click way to modify the "raw" argument's default value.
poly(`X1`, degree = 2, raw = TRUE)
in place of this:
poly(`X1`, degree = 2)
There is no point-and-click way to modify the "raw" argument's default value.
Additional Information
The Linear Regression feature uses a built-in Spotfire data function that runs a TIBCO Enterprise Runtime for R (TERR) script.
In the Spotfire desktop client, selecting "Tools > TERR Tools > Launch TERR Console" will open a TERR Console session in its own window.
In the TERR Console session, the following (case sensitive) commands will open TERR online help topics for TERR functions that are used by the Linear Regression feature:
?lm
?formula
?poly
In the Spotfire desktop client, selecting "Tools > TERR Tools > Launch TERR Console" will open a TERR Console session in its own window.
In the TERR Console session, the following (case sensitive) commands will open TERR online help topics for TERR functions that are used by the Linear Regression feature:
?lm
?formula
?poly
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