Displaying 20 results from an estimated 1000 matches similar to: "Help writing basic loop"
2005 Jun 08
2
Robustness of Segmented Regression Contributed by Muggeo
Hello, R users,
I applied segmented regression method contributed by Muggeo and got
different slope estimates depending on the initial break points. The results
are listed below and I'd like to know what is a reasonable approach handling
this kinds of problem. I think applying various initial break points is
certainly not a efficient approach. Is there any other methods to deal with
segmented
2011 Apr 13
1
print to .jpeg
Evening folks,
I'm trying to print a series of graphs to .jpeg using a variable as the
title, but run into the difficultly that I can't find a way to append the
file extension to the .jpeg (in this case extensionless!) files.
Example:
----
species.name="CussoniaHolstii"
dia<-10:100
biomass = -21.4863 + 0.5797 * (dia ^ 2)
biomass
jpeg(species.name)
plot (biomass,
2011 Jun 20
1
Quick R syntax question
Hi --
I had a pretty quick R question since unfortunately I have not been able to
find an answer on Google. It shouldn't take much more than a minute to
answer.
I'm trying to add up the major gleason grade and minor gleason grade for an
analysis of patients with prostate cancer. One column has values under
"Major Gleason" and another column has values under "Minor
2010 Apr 08
2
Overfitting/Calibration plots (Statistics question)
This isn't a question about R, but I'm hoping someone will be willing
to help. I've been looking at calibration plots in multiple regression
(plotting observed response Y on the vertical axis versus predicted
response [Y hat] on the horizontal axis).
According to Frank Harrell's "Regression Modeling Strategies" book
(pp. 61-63), when making such a plot on new data
2011 Dec 01
2
R endnote entry
I know citation() gives the R citation to be used in publications. Has
anyone put this into endnote nicely? I'm not very experienced with
endnote, and the way I have it at the momeny the 'R Development Core
Team' becomes R. D. C. T. etc.
Cheers.
2011 Sep 01
2
Help with creating date as POSIXct
Dear list,
I want to create a POSIX time vector as follows:
day <- as.character("110809")
time.t <- 1:3600
t.min <- time.t %/% 60
t.sec <- time.t-t.min*60
DATE <- as.POSIXct(strptime(paste(day,t.min,t.sec),"%y%m%d %M%S"))
Tail(DATE)
The problem is that the last element (3600) returns a NA and I don't
understand why. 600, 1200, 2400
2011 Mar 08
4
Make R 'Beep'
Dear all,
I would like to ask you if R can produce any kind of sound. It would be useful when code execution stops R to notify me by playing some sound.
Is that possible in R?
I would like to thank you in advance for your help
Best Regards
Alex
2011 Sep 22
2
How to adjust the y-axis range in barplot properly
Hello R-Users,
it might be a rather simple problem I have, but I couldn't find any
solution online. Thus, here is my problem:
I would like to adjust the y-axis range in a barplot, since all my
values are >70. Therefore I would like to only visualize the y-axis from
60-100 (example 1).
The problem is, the range of the y-axis is adjusted, but the barsize
stays the same and vanishes from
2011 Apr 22
2
statistic Q
Dear,
i am a student and I need help in comparing between different slopes and
finding whther there is a significant difference between them?
Thanks a lot
[[alternative HTML version deleted]]
2010 Apr 01
2
Adding regression lines to each factor on a plot when using ANCOVA
Dear R users,
i'm using a custom function to fit ancova models to a dataset. The data are
divided into 12 groups, with one dependent variable and one covariate. When
plotting the data, i'd like to add separate regression lines for each group
(so, 12 lines, each with their respective individual slopes). My 'model1'
uses the group*covariate interaction term, and so the coefficients
2009 Apr 08
2
Null-Hypothesis
Hello R users,
I've used the following help two compare two regression line slopes.
Wanted to test if they differ significantly:
Hi,
I've made a research about how to compare two regression line slopes
(of y versus x for 2 groups, "group" being a factor ) using R.
I knew the method based on the following statement :
t = (b1 - b2) / sb1,b2
where b1 and b2 are the two slope
2011 Sep 08
2
help subsetting data based on date AND time
Dear R Community,
I am new to R, and have a question that I suspect may be quite simple but is
proving a formidable roadblock for me. I have a large data set that
includes water-quality measurements collected over many 24-hour periods.
The date and time of sample collection are in a combined Date/Time field in
the format yyyy-mm-dd hh:mm:ss. I need to be able to subset the data for
analysis of
2005 Jan 23
4
survreg: fitting different location parameters
Hi R-Help!
My question: I have lifetime/failure data of machines with different
stress levels and i think an weibull/extreme value distribution would
fit this data. So I did:
model1 <- survreg(Surv(lfailure)~stress,data=steel,dist="extreme")
(where lfailure=log(failure))
Now I would like to do a likelihood ratio test to test the hypothesis
H0: location parameters of the
2008 May 04
4
improvement of Ancova analysis
Dear Helpers,
I just started working with R and I'm a bit overloaded with information.
My data is from marsupials reindroduced in a area. I have weight(wt),
hind foot
lenghts(pes) as continues variables and origin and gender as categorial.
condition is just the residuals i took from the model.
> names(dat1)
[1] "wt" "pes" "origin" "gender"
2005 Jan 20
1
Windows Front end-crash error
Dear List:
First, many thanks to those who offered assistance while I constructed
code for the simulation. I think I now have code that resolves most of
the issues I encountered with memory.
While the code works perfectly for smallish datasets with small sample
sizes, it arouses a windows-based error with samples of 5,000 and 250
datasets. The error is a dialogue box with the following:
"R
2012 Jan 17
2
Which date format to choose?
R offers a bewildering array of options when it comes to representing
dates and times (e.g, as.Date, chron, strptime, zoo, etc). Can anybody
recommend a document that compares the relative merit of each method? I'm
not looking for help with any one method, but rather a guide that
describes which method is best for a particular data analysis/plotting
goal.
Thanks,
Jake
[[alternative
2012 Mar 14
1
lme code help
Hi guys,
Got a few days left and I need to model a random effect of species on the
body mass (logM) and temperature (K) slopes. This is what i've done so far
that works:
model1<-lme(logSSP~logM + K,random=~1|species,data=data1)
model2<-lme(logSSP~logM + K,random=~K|species,data=data1)
model3<-lme(logSSP~logM + K,random=~logM|species,data=data1)
The one I now want is:
2002 May 28
1
passing model objects to anova()
Hi,
I'm fitting a glm to a dataset...
> objects()
[1] "pop.div.full" "speciation.data"
...and then performing model simplification to give a series of model
objects all of which have a common suffix.
> objects()
[1] "pop.div.full" "pop.div.gp.f.b.hm"
[3] "pop.div.gp.fb.hm"
2008 Jan 22
2
Help - linear regression
Hi,
I am trying a linear regression model where the dependent variable is the size of the heart corrected for the patient's height and weight. This is labelled as LAVI. The independent variables are race (european or non-eurpoean), age, sex (male or female) of the patient and whether they have diabetes and high blood pressure. sample size 2000 patients selected from a community.
when I
2010 Sep 29
1
Trying to avoid loop structure
Dear R-helpers,
I'm trying to associate linear coefficients (intercept and slope) to tens of thousands of observations based on a table with benchmark values.
#####Example - Value table and their corresponding coefficients (intercept and slope)
coef = data.frame(cbind(st=c(1:5),b = runif(5,0.3,5),a = seq(0.5,5,1)))print(coef)
#Example of observations to be computedobs = runif(20,1,5)print(obs)