Displaying 6 results from an estimated 6 matches for "troysocks".
2011 Jan 24
2
Implementing step-wise linear regression
Dear R fans,
I am trying to do step-wise linear regression using the F-test to decide
which variables to admit. Ewout Steyerberg suggests using the F-test for
this purpose.
I first build a model using no variables using lm(y ~ 1) and then using one
variable that is a strong predictor using lm(y ~ x). When I call var.test
on these two models, I do not get a significant p-value—0.07. But a
2010 Aug 07
2
R: Confidence Intervals for logistic regression
...istic.model)$coef
> >
> > est<-exp(sum.coef[,1])
> > upper.ci<-exp(sum.coef[,1]+1.96*sum.coef[,2])
> > lower.ci<-exp(sum.coef[,1]-1.96*sum.coef[,2])
> >
> > cbind(est,upper.ci,lower.ci)
> >
> > regards.
> >
> > 2010/8/6 Troy S <troysocks-twigs at yahoo.com>
> >
> >> Dear UseRs,
> >>
> >> I have fitted a logistic regression using glm and want a 95% confidence
> >> interval on a response probability. Can I use
> >>
> >> predict(model, newdata, se.fit=T)
> >>
>...
2008 Jun 30
1
Lattice : Single reference line/label at 0.05
r-friends--
I am trying to make a lattice plot with a single label at 0.05. A reference line at y=0.05 as well... This is what I have so far. The label reads 0.0 and there is a grid instead of a single reference line. Can someone help please?
Troy
x<-18:35
(pv<-1/(x-17))
xydf<-data.frame(x, pv)
print(xyplot(pv~x, data=xydf, type=c('p', 'g'),
ylim=c(0,1),
2008 Jun 13
0
Help with stat.table in Epi package,
R Fans--
I am having problems with the following code. It worked under R 2.6.0 but not in 2.7.0.
> library(Epi)
> df <- read.table( "c:/Documents and Settings/Troy S/My Documents/debug_chisq_080613b.txt")
> summary(df)
cvd agecat
Min. :0.0000 (0,40] :1
1st Qu.:0.0000 (40,60]:2
Median :0.0000
Mean :0.3333
3rd
2011 Aug 18
1
Using mixed models to analyze Longitudinal intervention
Dear R List,
I am trying to use mixed models to analyze an intervention and want to make
sure I am doing it correctly. The intervention is for lowing cholesterol
and there are two groups: one with an intervention and one without. The
subjects were evaluated a differing amount of time, so there were between 2
and 7 visits, equally spaced.
Sample output is below. TC is total cholesterol,
2012 Dec 03
4
Chi-squared test when observed near expected
Dear UseRs,
I'm running a chi-squared test where the expected matrix is the same as the
observed, after rounding. R reports a X-squared of zero with a p value of
one. I can justify this because any other result will deviate at least as
much from the expected because what we observe is the expected, after
rounding. But the formula for X-squared, sum (O-E)^2/E gives a positive
value. What