Displaying 20 results from an estimated 2000 matches similar to: "Box-Cox transformation in R"
2011 May 04
3
best subset regression in R
Dear All,
Could someone please give some advice the way to do linear modelling via best subset regression in R? I'd really appreciate for your kindness.
Thanks,
Kagba
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2009 Sep 08
1
[OT] "_" inserted in postings
Sorry if this is too "OT", but there is a particular relevance to
postings to R-help.
Of recent times, I have received several postings via R-help (and some
other mailing-lists) in which the "_" character is inserted where,
presumably, a space, " ", was intended. An example (received this
morning) is below, which (from the headers) was originally sent
through Yahoo
2010 Aug 13
2
Kalman filter
Dear All,
Could anyone?give me a hand?to suggest few packages in R to running Kalman
prediction and filtration ?
Thanks
Fir
2011 May 09
3
Recursive Indexing Failed
Dear all,
I would like to ask your help concerning an error message I get.
I have the following struct
str(CRagentInTime[[1]])
List of 2
$ timelag: int 0
$ CRagent:List of 50
..$ :List of 3
.. ..$ CRmap: num [1:256, 1:256] NA NA NA NA NA NA NA NA NA NA ...
.. ..$ xy : num [1:2] 10 177
.. ..$ sr : num [1:49] -94.9 -92.8 -79.5 -97.6 -78.4 ...
and I wanted to select all the sr fields
2009 Sep 05
8
Color index in image function
Dear All,
I was looking for the color index in?image function,?such as from topo.colors(n) and etc. but still never found it. For instance, from the help menu.
###########################################
# Volcano data visualized as matrix. Need to transpose and flip
# matrix horizontally.
image(t(volcano)[ncol(volcano):1,])
# A prettier display of the volcano
x <- 10*(1:nrow(volcano))
y
2009 Sep 23
4
Problem in graph plotting
Dear All,
Let:
dp: depth of the?river
tp: temperature with respect to depth
We can?have a simple scatter plot, between depth as y-axis and temperature as x-axis,?by using a?plot function as shown?below.
#####################?
dp <- c(1,4,3,2,5,7,9,8,9,2)
tp <- 1:10
plot(tp,dp, type= 'l')
#####################
?
Could someone advice me on?the way to?plot the same pair of
2010 Jan 22
4
How to seperate date and time into different columns?
Dear All,
I have a series of data in which the first column consist of a combination of date and time, for instance 17 April 2008 at 4.01pm, such data is recorded as:
4/17/2008 16:01
I'd like to seperate it into four different columns which consist of Day, Month,Year and Time, respectively.
Could someone please advice me on this mater?
Thank you,
Fir
2009 Sep 22
3
How to combine matrices?
Dear All,
Let a, b and c are?three matrices with same no. of column but different no. of row.
a <- matrix(1, 1, 2)
b <- matrix(2, 2, 2)
c <- matrix(3, 3, 2)
Could someone help me to combine these matrices together as a single matrix?
Thank you
Fir
2010 Apr 02
4
Derivative of a smooth function
Dear All,
I've been?searching for?appropriate codes to compute the rate of change and the curvature?of ?nonparametric regression model whish was denoted by a smooth function?but?unfortunately?don't manage to?do?it. I presume that such characteristics from a smooth curve can be determined by the first and second derivative operators.
The following are the example of fitting a
2011 Sep 01
4
Question about BIC of two different regression models? how should we compare two regression models?
Hi All,
In order to compare two different logistic regressions, I think I need to compare them based on their BIC values, but I am not sure if the smaller BIC would mean a better model or the reverse is true?
Thanks a lot,Andra
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2006 Feb 09
3
about Cox-Box transformation
Dear R-users,
I am using R version 1.8.0-1 under Suse 8.2.
I need to use the boxcox command because I want to apply a Cox-Box
transformation to a vector of rainfall values.
Within the libraries, the MASS library is present, but I don't know
whether this means that is automatically installed or not.
The command doesn't work. What do I have to do in order to make it
working? Is just a
2009 May 19
4
nlrwr package. Error when fitting the optimal Box-Cox transformation with two variables
Dear all:
I'm trying to fit the optimal Box-Cox
transformation related to nls (see the code
below) for the demand of money data in Green (3th
Edition) but in the last step R gives the next
error message.
Error en
`[.data.frame`(eval(object$data), ,
as.character(formula(object)[[2]])[2]) :
undefined columns selected.
?Any idea to solve the problem?
Thanks in advance,
2003 Nov 20
3
nls, nlrq, and box-cox transformation
Dear r-help members
I posted this message already yesterday, but don't know whether it
reached you since I joined the group only yesterday.
I would like to estimate the boxcox transformed model
(y^t - 1)/t ~ b0 + b1 * x.
Unfortunately, R returns with an error message when I try to
perform this with the call
nls( I((y^t - 1)/t) ~ I(b0 + b1*x),
start = c(t=1,b0=0,b1=0), data = mydataframe)
2004 Dec 20
1
why use profile likelihood for Box Cox transformation?
Hi All,
I'm analysing some data that is conventionally modelled as log(Y) = a + bX + e. However, using the boxcox function, it appears that the optimum value of lambda is approx 0.05. I have 40 data sets of differing sizes and for about half of these, lambda is significantly non-zero. So, it is worth looking into.
The alternative model, Y^lambda = a + bX + e, has been explored before by
2009 Oct 15
2
Estimation in a changepoint regression with R
Dear All,
I'm trying to do the estimation in a changepoint regression problem via R, but never found any suitable function which might help me to do this.
Could someone give me a hand?on this matter?
Thank you.
2005 Jan 25
1
Box-Cox / data transformation question
Dear R users,
Is it reasonable to transform data (measurements of plant height) to the
power of 1/4? I?ve used boxcox(response~A*B) and lambda was close to 0.25.
Regards,
Christoph
2009 Oct 02
2
How to speed up R with version 2.9.2?
Dear All,
I'm sorry if my question does not suit with this R group.
I have recently installed?R software with version 2.9.2, but i found the program took almost 1 minute as soon as it was opened, before it can be used. However,?the previous version 2.9.1 only take few seconds?after the menu bar was clicked. This circumstance has caused me to wait for couple of minutes as several R windows
2009 Sep 08
1
Derivative of nonparametric curve
Dear All,
I'm looking for?a way on computing the derivative of first and second order?of a smoothing curve produced by a nonprametric regression. For instance, if we run the R script below, a smooth nonparametric regression curve is produced.
provide.data(trawl)
Zone92?? <- (Year == 0 & Zone == 1)
Position <- cbind(Longitude - 143, Latitude)
dimnames(Position)[[2]][1] <-
2009 Sep 24
3
Color of the plot which correspond to the group of the observations
Dear All,
?
Let:
dp: depth of the river
tp: temperature with respect to depth
These pair of observations are in 3 different groups i.e:
Obs. 1,3,5,7?from the first group
Obs. 2,4 and?10?from second group
Obs 6,8 and 9?from third group.
We can have a simple scatter plot, between depth as y-axis and temperature as x-axis, with each pairs are denoted by a red dot, by using a plot function shown
2007 Jan 22
1
Finding the effect of Box-Cox transformation using "vis.boxcoxu"
Dear all R users,
I have a dataset 'data' and I want to see the effect of Box-Cox
transformation on it Interactively for different lambda values. I already
got a look on function "vis.boxcoxu" in package "TeachingDemos". But I
didn't find any option to put user's own dataset. Can anyone tell me how to
put my own dataset here i.e. "data"?
Thanks and