Mark Difford wrote:
ldb (?),
I am trying to extract significance levels out of a robcov+ols call....
However, I can't figure out how to get to the significance (Pr>ltl).
It is obviously calculating it because the call:
It's calculated in print.ols(). See extract below. To see the whole
function, do
print.ols
## Extract from print.ols in package Design
se <- sqrt(diag(x$var))
z <- x$coefficients/se
P <- 2 * (1 - pt(abs(z), rdf))
co <- cbind(x$coefficients, se, z, P)
dimnames(co) <- list(names(x$coefficients), c("Value", "Std. Error",
"t", "Pr(>|t|)"))
print(co)
HTH, Mark.
In addition to what Mark said, note that it is usually an accident when
a variable has only one degree of freedom in the model. So in general
you might use the matrix that is output by anova.Design.
Frank
ldb-5 wrote:
I am trying to extract significance levels out of a robcov+ols call.
For background: I am analysing data where multiple measurements(2 per
topic) were taken from individuals(36) on their emotional reaction
(dependent variable) to various topics (3 topics). Because I have
several emotions and a rotation to do on the topics, I'd like to have
the results pumped into a nice table.
answer<-robcov(ols(emotion ~ topic,x=TRUE,y=TRUE),individual)
>From the robcov help it warns me:
Adjusted ols fits do not have the corrected standard errors printed with
print.ols. Use sqrt(diag(adjfit$var)) to get this, where adjfit is the
result of robcov.
So I can get to the standard error by:
answer.se<-sqrt(diag(answer$var))
I can get to the coefficients by:
answer.co<-coefficients(answer)
I can get to the t-values by:
answer.t<-coefficients(answer)/ sqrt(diag(answer$var))#t-value
However, I can't figure out how to get to the significance (Pr>ltl).
It is obviously calculating it because the call:
answer
provides it, but I can't figure out where it is getting it from or how
it is calculating.
thanks for any help.
ldb
______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Frank E Harrell Jr Professor and Chair School of Medicine
Department of Biostatistics Vanderbilt University
______________________________________________
[email protected] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
