Displaying 20 results from an estimated 800 matches similar to: "help to setting a multiple (linear) regression model with a 5% significance level (threshold) for the inclusion of the model variables."
2012 Jan 25
4
help to slip a file name using "strsplit" function
Dear Researchers,
I have several files as this example: Myfile_MyArea1_sample1.txt
i wish to split in "Myfile", "MyArea1", "sample1", and "txt", becasue i
need to use "sample1" label. I try to use "strsplit" but I am able just to
split as "Myfile_MyArea1_sample1" and "txt" OR "Myfile", "MyArea1",
2012 Feb 15
3
R citation for the 2012
Dear Reasearchers,
I am writing a report and i need (and wish) cite R. somebody know the
citation of R for the 2012? or the more actual?
thanks in advance
Gianni
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2012 Oct 29
2
the right reference for the R Stats package for a scientific journal
Dear Members list,
I am writing a paper for a research where i used "the R Stats package". No
one knows the right reference for this package?
Thanks in Advance
Gianni
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2012 Jan 27
2
help with Box plot
Dear researchers
I wish to plot a box plot without the mean line (the black line) and the i
wish a full line for the standard deviation
This is an example
mytest <- c(2.1,2.6,2.7,3.2,4.1,4.3,5.2,5.1,4.8,1.8,1.4,2.5,2.7,3.1,2.6,2.8)
boxplot(mytest)
really thanks
Gianni
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2012 May 16
1
how disable the Error massage in read.table() " no lines available in input"
Dear Researchers,
I am looking a way to disable the Error massage in read.table() as warn =
TRUE in readLines(), when the lines are empty
Error in read.table(con, header = F, sep = " ", nrow = n) :
no lines available in input
thanks for all suggestions
Gianni
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2012 Jan 30
2
plot with ylim with regural interval
Dear Researchers,
sorry for the easy question but Is it possible to plot with an interval of
1 or .5 in a plot using ylim?
Thanks
gianni
x = 0:10;
y = 0:10;
plot(x~y,ylim=c(0,10),las=1)
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2012 Mar 23
2
plot a BARPLOT with sd deviation bar up and down
dear Researchers,
i am looking for a function to plot a barplot for each mean value and the
related standard deviation, and i can close my week. This is an example of
my data set.
really Thanks in advance for any help or suggestions
Gianni
My.mean <- data.frame(Mean=c(0.4108926,0.3949009,0.4520346,
0.4091665,0.4664066,0.3048296,0.4297226,0.4056383,
2012 Jun 15
1
some help to improve "hist to plot relative frequencies"
Dear Researches,
sorry for disturb. I wish to improve my figure in R plotting the relative
frequencies of my data set.
library(lattice)
a <- c(0,0,0,1,1,2,4,5,6,7,7,7,7,7,8,8,8,8,9,9,9,9,10,10,11)
histogram(a, xlab="myData")
what i wish to do is:
1) invert the order of X and Y (eg: Precent of Total on X-axis and "MyData"
on X-axis)
2) plot not the bar of histogram but a
2012 Mar 16
1
help to split a ID column in a data.frame and create a new ID column
Dear Researchers,
I have a data.frame with 2 columns like this:
mydf <-
data.frame(value=c(1,2,3,4,5),ID=c("Area_1","Area_2","Area_3","Area_4","Area_5"))
> mydf
value ID
1 1 Area_1
2 2 Area_2
3 3 Area_3
4 4 Area_4
5 5 Area_5
I need to convert the *ID *in the following version
> mydf
value ID newID
2012 Jan 27
1
Help boxplot to add mean, standard error and/or stadard deviation
Dear researchers
I wish to plot a box plot without the mean line (the black line) and plot
only the mean (red square). Futhermore, is it possible to add standard
error and/or stadard deviation?
This is an example
mytest <- c(2.1,2.6,2.7,3.2,4.1,4.3,5.2,5.1,4.8,1.8,1.4,2.5,2.7,3.1,2.6,2.8)
boxplot(mytest,lty = "solid")
means <- mean(mytest,na.rm=TRUE)
points(means, pch = 22, col
2012 Jun 25
1
special simbol (±) in a legend
dear reserachers,
I am looking for a expression about a special symbol (±) in a Legend and
add on front of "Mean ± SD" the symbol of bracket
sorry if the example is not great
disptest <- matrix(rnorm(10),nrow=10)
disptest.means<- rowMeans(disptest)
plot(1:10,disptest.means)
dispersion(1:10,disptest.means,(disptest.means+disptest
),(disptest.means-disptest
2012 Jul 02
1
error to convert a Compute A^-1 B from Matlab to R using solve(A, B)
Dear Researchers,
I need to convert the following equation in R from Matlab
a = [x y ones(size(x))];
b = [-(x.^2+y.^2)];
a\b
ans =
-9.9981
-16.4966
-7.6646
my solution in R is:
a = cbind(x,y,rep(1,length(x)))
b = cbind(-(x^2+y^2))
> head(a)
x y
[1,] 14.45319 5.065726 1
[2,] 14.99478 5.173893 1
[3,] 14.64158 5.616916 1
[4,] 14.61803 6.624069 1
[5,] 14.19997
2012 Nov 07
1
total number of citations for R project
Dear Member list,
is there a weblink or a paper where the total number of citations for R
project is report?
Thanks in advance
Gianni
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2011 Dec 05
1
explanation why RandomForest don't require a transformations (e.g. logarithmic) of variables
Dear Researches,
sorry for the easy and common question. I am trying to justify the idea of
RandomForest don't require a transformations (e.g. logarithmic) of
variables, comparing this non parametrics method with e.g. the linear
regressions. In leteruature to study my phenomena i need to apply a
logarithmic trasformation to describe my model, but i found RF don't
required this approach.
2012 Feb 26
3
count how many row i have in a txt file in a directory
Dear Researchers,
I have a large TXT (X,Y,MyValue) file in a directory and I wish to import
row by row the txt in a loop to save only the data they are inside a buffer
(using inside.owin of spatstat) and delete the rest. The first step before
to create a loop row-by-row is to know how many rows there are in the txt
file without load in R to save memory problem.
some people know the specific
2007 Jun 15
2
model.frame: how does one use it?
Philipp Benner reported a Debian bug report against r-cran-rpart aka rpart.
In short, the issue has to do with how rpart evaluates a formula and
supporting arguments, in particular 'weights'.
A simple contrived example is
-----------------------------------------------------------------------------
library(rpart)
## using data from help(rpart), set up simple example
myformula <-
2011 Nov 17
1
tuning random forest. An unexpected result
Dear Researches,
I am using RF (in regression way) for analize several metrics extract from
image. I am tuning RF setting a loop using different range of mtry, tree
and nodesize using the lower value of MSE-OOB
mtry from 1 to 5
nodesize from1 to 10
tree from 1 to 500
using this paper as refery
Palmer, D. S., O'Boyle, N. M., Glen, R. C., & Mitchell, J. B. O. (2007).
Random Forest Models
2009 Oct 11
3
passing field name parameter to function
Hi,
I am passing a data frame and field name to a function. I've figured out how
I can create the formula based on the passed in field name, but I'm
struggling to create a vector based in that field.
for example if I hard code with the actual field name
Y = df$Target, everything works fine.
but if I use the passed in parameter name, it doesn't give me what I want,
Y =
2010 Jan 05
1
Is the Intercept Term always in First Position?
Dear All,
I have a question about formulas and model.matrix(). If one specifies a model via a formula, the corresponding design matrix can be obtained with the model.matrix() function. For example:
x1 <- c(1,4,2,3,5)
x2 <- c(1,1,2,2,2)
myformula <- ~ x1 + factor(x2)
model.matrix(myformula)
My question is: If an intercept term is in the model (like in the example above), is it always
2010 Jan 01
1
Questions bout SVM
Hi everyone,
Can someone please help me in these questions?:
1)if I use crossvalidation with svm, do I have to use this equation to calculate RMSE?:
mymodel <- svm(myformula,data=mydata,cross=10)
sqrt(mean(mymodel$MSE))
But if I don’t use crossvalidation, I have to use the following to calculate RMSE:
mymodel <- svm(myformula,data=mydata)
mytest