Displaying 20 results from an estimated 10000 matches similar to: "fit the series data"
2008 Sep 23
3
Generating series of distributions with the same skewness and different kurtosis or with same kurtosis and different skewness?
Dear R users,
I hope to explain the concepts of skewness and kurtosis by generating
series of distributions with same skewness and different kurtosis or with
same kurtosis and different skewness, but it seems that i cannot find the
right functions.
I have searched the mailing list, but no answers were found.
Is it possible to do that in R? Which function could be used?
Thanks a lot.
--
2007 Sep 13
2
handle dates in R?
Dear Rusers,
I have some data in .csv file like "2004-8-1" and "2004-10-1", and i need
to convert them into days from the origin (January 1, 1960).
I have tried the function date.mmddyyyy(), but cannot get it. Anybody can
show me how to handle the date data?
Thanks very much!
My dataset like:
time
2004-8-1
2004-10-1
2001-9-1
2002-9-1
--
With Kind Regards,
2006 Apr 13
2
a question on subset a dataset
Dear R-users,
I generate a dataset "d", and want to get a subset from it.
**
*z<-rnorm(9)
coords<-cbind(x=c(1,1,1,2,2,2,3,3,3),y=c(1,2,3,1,2,3,1,2,3))
d<-SpatialPointsDataFrame(coords, data.frame (z=z[1:9]))*
The result*/dataset* is
coordinates z
1 (1, 1) 1.41173570
2 (1, 2) 0.18546503
3 (1, 3) -0.04369144
4 (2, 1) -0.21591338
5 (2, 2)
2007 Oct 02
2
How to add legend for image()?
Dear friends,
The following is an example to explain my question. I want to get a
legend which will show the z-values according to different colors in image()
function.
x<-sort(runif(10)) #x-coordinates
y<-sort(runif(10)) #y-coordinates
z<-matrix(runif(100),nrow=10) #attributes values
image(x,y,z,col=gray((6:3)/6))
# legend(x,y,legend=z,col=gray((6:3)/6)) #error. the colors should
2007 Aug 17
3
Is there any good tools to facilitate us to create R functions?
Dear R users,
We have some programs for the specific task in our research, but they were
very commonly used. We want to make some functions for them, anybody can
recommend any good tools to facilitate us to create R functions even without
going deep into the theories of R functions ?
Any suggestions or help are greatly appreciated.
--
With Kind Regards,
oooO:::::::::
(..):::::::::
2008 Jan 01
3
Specify a correct formula in R for Piecewise Linear Functions?
Dear all,
I have two variables, y and x. It seems that the relationship between them
is Piecewise Linear Functions. The cutpoint is 20. That is, when x<20, there
is a linear relationship between y and x; while x>=20, there is another
different linear relationship between them.
How can i specify their relationships in R correctly?
# glm(y~I(x<20)+I(x>=20),family = binomial, data =
2006 Nov 19
2
questions on adding reference line?
Dear Ruser,
I use abline() function to add the reference line successfully, but i
can't display the values corresponding to the reference line on the x/y
axis, anybody knows how to display it?
*My simulated programs:*
y<-rnorm(50)
plot(x,y)
abline(v=0.5) *#my question is how to display x=0.5 in the x axis?*
Thanks in advance.
--
With Kind Regards,
oooO:::::::::
(..):::::::::
2007 Oct 12
3
Anybody has ever met the problem to add a legend to a figure generated by image()?
Dear friends,
Anybody has ever met the problem to add a legend to a figure generated by
image()? I have three variables,x,y and z.
x and y are the coordinates, and z is the third values. we can use image(x,
y, z,...) to generate a figure according to the z-values, but the problem is
the figure legend. How can the legend be added to a figure generated
by image()? Note that filled.contour() can
2006 Jul 02
2
how to recode in my dataset?
Dear Rusers,
My question is about "recode variables". First, i'd like to say
something about the idea of recoding:
My dataset have three variables:type,soiltem and airtem,which means
grass type, soil temperature and air temperature. As we all known, the
change of air temperature is greater than soil temperature,so the
values in those two different temperaturemay represent different
2006 Aug 31
3
what's wrong with my simulation programs on logistic regression
Dear friends,
I'm doing a simulation on logistic regression model, but the programs can't
work well,please help me to correct it and give some suggestions.
My programs:
data<-matrix(rnorm(400),ncol=8) #sample size is 50
data<-data.frame(data)
names(data)<-c(paste("x",1:8,sep="")) #8 independent variables,x1-x8;
#logistic regression model is
2006 Oct 12
2
how to get the variance-covariance matrix/information of alpha and beta after fitting a GLMs?
Dear friends,
After fitting a generalized linear models ,i hope to get the variance of
alpha,variance of beta and their covariance, that is , the
variance-covariance matrix/information of alpha and beta , suppose *B* is
the object of GLMs, i use attributes(B) to look for the options ,but can't
find it, anybody knows how to get it?
> attributes(B)
$names
[1] "coefficients"
2006 Aug 20
2
how to the p-values or t-values from the lm's results
Dear friends,
After running the lm() model, we can get summary resluts like the
following:
Coefficients:
Estimate Std. Error t value Pr(>|t|)
x1 0.11562 0.10994 1.052 0.2957
x2 -0.13879 0.09674 -1.435 0.1548
x3 0.01051 0.09862 0.107 0.9153
x4 0.14183 0.08471 1.674 0.0975 .
x5 0.18995 0.10482 1.812 0.0732 .
x6 0.24832 0.10059 2.469 0.0154 *
x7
2006 Jun 20
3
how to put the results of loop into a dataframe
Dear friends,
suppose i want to do the following caulation for 100 times, how to put the
results of x , y and z into the same dataframe/dataset?
x<-runif(1)
y<-x+1
z<-x+y
thanks in advance!
--
Kind Regards,
Zhi Jie,Zhang ,PHD
Department of Epidemiology
School of Public Health
Fudan University
Tel:86-21-54237149
[[alternative HTML version deleted]]
2006 Apr 12
2
subset a matrix
Dear friends,
I have a (20*30) matrix,and want to get a subset of it like the following:
The original matrix: rows:1,2,3,....20; columns:1,2,3,....30
I want to get my subset of The original matrix and delete others:
rows:1,3,5,7,...19; columns:1,3,5.....29
--
Kind Regards,Zhi Jie,Zhang ,PHDDepartment of EpidemiologySchool of Public
HealthFudan UniversityTel:86-21-54237149
2007 Dec 31
2
help on ROC analysis
Dear all,
Some functions like 'ROC(Epi)' can be used to perform ROC analyssi, but it
needs us to specify the fitting model in the argument. Now i have got the
predicted p-values (0,1) for the 0/1 response variable using some other
approach, see the following example dataset:
id mark predict.pvalue
1 1 0.927
2 0 0.928
3 1 0.928
..................
2006 Aug 23
1
how to complete this task on data management
Dear friends,
When i clean my dataset , i met a difficulty
suppose my data set is :
*> data<-data.frame(x=c(1:5,1,2,3))
> data
x
1 1
2 2
3 3
4 4
5 5*
6 1
7 2
8 3
Now i need to add the data which are less than 3.5 at the bottom, not
including the top data, so the results should be :
x
1 1
2 2
3 3
4 4
5 5
*6 6*
I tried to use " data[data$x>3.5,]" to do it , but it also
2006 Jul 13
3
set the bahavior that R deal with missing values?
Dear Rusers,
The default behavior in R when performing a regression model with missing
values is to exclude any case that contains a
missing value? How could i set the bahavior that R deal with missing values?
e.g.:
exclude cases listwise
exclude cases pairwise
replace with mean
Thanks very much!
--
Kind Regards,
Zhi Jie,Zhang ,PHD
Department of Epidemiology
School of Public Health
Fudan
2007 Sep 17
2
What's the corresponding function in R for lo() function in S-PLUS?
Dear friends,
In S-PLUS, we can use the following argument, but not in R.
mode12 <- gam(score1 ~ lo(latitude) + lo(longitude))
I searched the help in S-PLUS, it says lo() Allows the user to specify a
Loess fit in a GAM formula, but i didn't find the correponding function in
R.
Anybody knows how to do the similar task in R?
Thanks very much.
--
With Kind Regards,
oooO:::::::::
2006 Jul 03
2
could i change the ouput style on summary?
Dear friends,
summary() doesn't give a good ouput style,e.g.:
grass soiltem airtem gheight
humidity altitude
diluo :38 Min. :15.90 Min. :17.70 Min. : 8.00 Min. :
0.2360 high: 43
huanghuacai:32 1st Qu.:19.32 1st Qu.:22.60 1st Qu.:40.00 1st Qu.:
0.3190 low :119
hucao :46 Median :20.20 Median :25.30 Median :60.00
2006 Mar 22
1
How to join "specific Special Interest Group (=: SIG) mailing lists"
there are several specific Special Interest Group (=: SIG) mailing
lists,and i'm interested in the"R-sig-Geo :R Special Interest Group on
using Geographical data and Mapping ",but can't find how to join it,
could anybody tell me how to do that? thank u very much!
--
Kind Regards,Zhi Jie,Zhang ,PHDDepartment of EpidemiologySchool of
Public HealthFudan