Displaying 12 results from an estimated 12 matches for "jokel".
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joke
2011 Jul 18
1
Extract confidence intervals from rma object (metafor package)
...package. I would like
to extract values of the confidence intervals of the effect sizes of the
single studies from an rma object. Those values are printed out when
plotting a forest plot using the forest function on the rma object, however
I was not able to locate them.
Many thanks for your help!
Jokel
[[alternative HTML version deleted]]
2012 Apr 12
1
Using dcast with multiple functions to aggregate
...itiy,
I am trying to use multiple functions for aggregation within a function
call for dcast. However this seems to result in an error. Also I have not
managed to make dcast() work with fun.aggregate=sd. Please find attached
some example code using the ChickWeight data.
Many thanks for your help!
Jokel
#Chick weight example
names(ChickWeight) <- tolower(names(ChickWeight))
sd(ChickWeight$weight) # works fine
mean(ChickWeight$weight) # works fine
length(ChickWeight$weight) # works fine
chick_m <- melt(ChickWeight, id=2:4, na.rm=TRUE)
dcast(chick_m, time~variable, mean) # works fine...
2010 Aug 25
1
Estimate average standard deviation of mean of two dependent groups
...f two variables:
SD=SQRT(SD_A^2 + SD_B^2 + 2*r*SD_A*SD_B)
with SD_B and SD_B being the standard deviation of A and B. And r*SD_A*SD_B
being the covariance of A and B.
Would this formula also be valid if I want to average (and not sum) my two
variables?
Many thanks for any help & best wishes,
Jokel
[[alternative HTML version deleted]]
2012 Jun 24
2
Power calculation using pwr.t.test()
...ould need n=400 subjects
(200 in each group). This is seems so incredibly high that I mistrust my
results & wanted to ask whether I miscalculated n?
library(pwr)
pwr.t.test(d=0.28,sig.level=0.05,power=0.8,type="two.sample",alternative="two.sided")
Many thanks for you help!
Jokel
[[alternative HTML version deleted]]
2011 Jul 27
1
Converting F-value from ANOVA to cohen's d in meta-analysis (metafor-package)
...one group in the
other studies (B=C,D). Is there a way?
The handbook of research synthesis and meta-analysis By Harris M. Cooper
says that:
d=sqrt((F*(n1+n2)/n1*n2)) for ANOVA (one-factor with two-levels)
but does this also hold for ANOVA (one-factor with three levels)?
Many thanks for your help!
Jokel
[[alternative HTML version deleted]]
2011 Aug 05
1
Main-effect of categorical variables in meta-analysis (metafor)
...amp; B)?
However I am interested in the main-effects and the interaction of these two
covariates and the dummy-coding would only allow to detect the effect of one
level of one factor. Would there be a way to assess main-effects and
interactions (something like an meta-analysis-ANOVA)?
Many thanks,
Jokel
[[alternative HTML version deleted]]
2012 Jul 24
1
Annotate forest plot 'forest.rma()' for meta-analysis with metafor package
...pos=4)
text(6, 15, "Relative Risk [95% CI]", pos=2)
par(op)
Is there a way to define the colum names' position relatively to the plot
so they would be adequately positioned no matter what is the number of
studies included in the plot?
Many thanks for your help!,
Jokel
[[alternative HTML version deleted]]
2012 Feb 11
1
Embed R code in online database
Dear R-List!
I would like to embed R code in an online database such as i.e. a google
spreadsheet in way that users can add data to the database and that R's
calculations are updated automatically and i.e. given out in the
spreadsheet. Maybe even graphs could be updated online? Is there a way to
implement this?
Many thanks!
J.
[[alternative HTML version deleted]]
2009 Jun 09
0
calculate effect size from p-value?
Dear R-List!
Is there any function (apparently for BioStat there is!) to calculate
effect sizes with the p-values and sample sizes?
That would be really useful for meta-analysis!
Thanks for the help!
Jokel
2011 Sep 24
0
Assessing prediction performance of SVM using e1071 package
...ting the set
into two sets using one set for training of the svm and the other for
testing the predictive power of the trained svm.
My understanding would be that (A) and (B) are alternative ways to estimate
the performance of the svm. Or would I have to implement both?
Many thanks for your help!
Jokel
[[alternative HTML version deleted]]
2011 Sep 27
0
Workflow for binary classification problem using svm via e1071 package
...y to use first (A) then do grid-search (via the
tune command) to find the best hyperparameters and then test the trained svm
by applying it to the test set? And in case I use a linear kernel instead of
RBF, I guess I do not need to run grid-search as there are no
hyperparameters to estimate?
BEst,
Jokel
[[alternative HTML version deleted]]
2012 Apr 15
0
correct implementation of a mixed-model ANOVA in R
...factor and control for re-test effects by including
'session'.
Could you advice me regarding the proper implementation of my model? Also I
am happy about any pointers to R-related literature.
Please find below some dummy data and initially model formulation.
Many thanks & best wishes,
Jokel
# some dummy data
data <- structure(list(subject = structure(c(1L, 1L, 1L, 1L, 1L, 1L,
2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L,
4L, 4L, 5L, 5L, 5L, 5L, 5L, 5L), .Label = c("1", "2", "3", "4",
"5"), class = "factor&quo...