Re: [R] interpret significance from the contr.poly() function

2011-02-03 Thread RICHARD M. HEIBERGER
You can use the summary with the split argument. See ?summary.aov for an example. This gives similar results to the regression coefficients approach that Ista Zahn suggested. I usually prefer the ANOVA table approach for factors. On Thu, Feb 3, 2011 at 3:36 AM, Asan Ramzan wrote: > Hello R-he

Re: [R] interpret significance from the contr.poly() function

2011-02-03 Thread Ista Zahn
By fitting some kind of model. contr.poly doesn't fit a model or test significance, it just sets contrasts. Here is an example data(mtcars) > mtcars$carb <- factor(mtcars$carb) > contrasts(mtcars$carb) <- contr.poly(n=levels(mtcars$carb)) > contrasts(mtcars$carb) .L .Q .C

[R] interpret significance from the contr.poly() function

2011-02-03 Thread Asan Ramzan
Hello R-help (sorry if this message gets posted twice, i think I may have accidently postponed it) I don’t know how to interpret significance from the contr.poly() function . From the example below : how can I tell if data has a significant Linear/quadratic/cubic trend? > contr.poly(4, c(1,2,4

[R] interpret significance from the contr.poly() function

2011-02-03 Thread Asan Ramzan
Hello R-help I don’t know how to interpret significance from the contr.poly() function . From the example below : how can I tell if data has a significant Linear/quadratic/cubic trend? > contr.poly(4, c(1,2,4,8))               .L         .Q          .C [1,] -0.5128