Displaying 3 results from an estimated 3 matches for "psamp".
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samp
2011 Dec 06
2
Why can't I figure this out? :S
...arently need to be able to find and isolate
influencial observations. Problem, I have no idea what the error means and
where it may be from in the code.
error I get is below the code
{
## OLS results
NameC<- lm(gpanew~female+female:lastinit+agenew+canadian+mom_ed+yearstudy)
## default: choose psamp = quantile
n <- length(residuals(NameC))
k <- length(coef(NameC))
if(is.null(quantile)) quantile <- c(floor((n + k + 1)/2),
floor((n + k)/2))
quantile <- rep(quantile, length.out = 2)
if(is.null(psamp)) psamp <- quantile[1]
## LTS results with robust residuals
NameC_lts <-
lqs(gp...
2003 Jul 30
2
robust regression
...uot;contr.sum")))
Error: lqs failed: all the samples were singular
Robust regression with M-estimators works (also regular least square
fits, of course):
rlm.formula(formula = obs ~ y + s - 1, method = "M", contrasts = list(s
= ("contr.sum")))
I tried an exact sampling (psamp="exact"), but I keep getting syntax
errors. Any idea how I can make the first one work?
Thanks,
joerg
--
----------------------------------------------------------
J?rg Schaber
Instituto Cavanilles de Biodiversidad y Biologia Evolutiva
Universidad de Valencia Tel.: ++34...
2005 Oct 06
0
a question about LMS and what constitutes outliers
...ich the original Rousseeuw et al.
program points out that observations 1,2,3,4 and 21 are outliers.
This conslusion is arrived at by testing whether the residual is greater
than 2.5 * standard error
Netx I ran lqs as:
m <- lqs(stackloss[,-4], stackloss[,4], method='lms', control=list
(psamp=4, nsamp='exact', adjust=TRUE))
(I ran it exhaustively since that was how I ran the original program
from Rousseeuw)
The coefficients obtained from lqs() are more or less identical to that
obtained by the original program. However the scale estimates do not
match. I assume that this would...