Displaying 3 results from an estimated 3 matches for "upper95".
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2011 May 22
1
How to calculate confidence interval of C statistic by rcorr.cens
...of
logistic regression model using rcorr.cens in rms package. I wrote a
brief function for this purpose as the followings;
CstatisticCI <- function(x) # x is object of rcorr.cens.
{
se <- x["S.D."]/sqrt(x["n"])
Low95 <- x["C Index"] - 1.96*se
Upper95 <- x["C Index"] + 1.96*se
cbind(x["C Index"], Low95, Upper95)
}
Then,
> MyModel.lrm.rcorr <- rcorr.cens(x=predict(MyModel.lrm), S=df$outcome)
> MyModel.lrm.rcorr
C Index Dxy S.D. n
missing uncensored
0.8222785...
2011 Nov 20
1
Cox proportional hazards confidence intervals
...ventions. I can successfully
obtain the LR, Wald, and Score test p-values from the coxph.object, as
well as the hazard ratio as follows:
formula.obj = Surv(days, status) ~ type
coxph.model = coxph(formula.obj, df)
fit = summary(coxph.model)
hazard.ratio = fit$conf.int[1]
lower95 = fit$conf.int[3]
upper95 = fit$conf.int[4]
logrank.p.value = fit$sctest[3]
wald.p.value = fit$waldtest[3]
lr.p.value = fit$logtest[3]
I had intended to report logrank P values with the hazard ratio and CI
obtained from this function. In one case the P was 0.04 yet the CI
crossed one, which confused me, and certainly will...
2011 Jul 20
0
Cleveland Dot plots: tick labels and error bars
...ption I've observed is from:
http://www.unc.edu/courses/2010fall/ecol/563/001/docs/solutions/assign2.htm
It seems to use the following panel function to create 95% conf. intervals:
panel=function(x,y) {
panel.grid(v=0, h=-6, lty=3)
panel.segments(new.data$lower95, as.numeric(y), new.data$upper95,
as.numeric(y), lty=1, col=1)
panel.segments(new.data$lower50, as.numeric(y), new.data$upper50,
as.numeric(y), lty=1, lwd=4, col='grey60')
panel.xyplot(x, y, pch=16, cex=1.2, col='white')
panel.xyplot(x, y, pch=1, cex=1.1, col='black')
panel.abline(v=0, col=2, lty=2)
}...