Displaying 20 results from an estimated 2000 matches similar to: "Bland-Altman method to measure agreement with repeated measures"
2011 Feb 24
1
accuracy of measurements
Dear R people
Could you please help with following
Trying to compare accuracy of tumor size evaluation by different
methods. So data looks like
id true metod1 method2 ...
1 2 2 2.5
2 1.5 2 2
3 2 2 2
etc.
Could you please give a hint how to deal with that.
Seems like {merror} does not suite to me because I am trying to compare
accuracy of measurements with their true known values not just
2000 Apr 25
2
[R) Bland Altman plot (was: paste ?)
> De : Bill Venables <venables at acland.qld.cmis.csiro.au>
> Objet : Re: [R] paste ?
> Date?: mardi 25 avril 2000 08:45
>
(...)
> Secondly, I'm curious about the history of this kind of plot.
> I've only heard it called a "Tukey mean difference" plot, (and
> Trellis graphics has a function, tmd(), that does it, but no one
> knows about it...).
2013 Jul 18
1
Bland Altman summary stats for all column combinations
Hello,
I have the following data.frame
structure(list(Study = structure(c(1L, 2L, 3L, 4L, 5L, 6L, 7L,
8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 1L,
2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L, 15L,
16L, 17L, 18L, 19L, 1L, 2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L,
11L, 12L, 13L, 14L, 15L, 16L, 17L, 18L, 19L, 1L, 2L, 3L, 4L,
5L, 6L, 7L, 8L, 9L, 10L, 11L, 12L, 13L, 14L,
2011 Sep 20
5
help in interpreting paired t-test
Dear all;
A very basic question. I have the following data:
************************************************************************************
A <- 1/1000*c(347,328,129,122,18,57,105,188,57,257,53,108,336,163,
62,112,334,249,45,244,211,175,174,26,375,346,153,32,
89,32,358,202,123,131,88,36,30,67,96,135,219,122,
89,117,86,169,179,54,48,40,54,568,664,277,91,290,
2010 Aug 25
2
Comparing samples with widely different uncertainties
Hi
This is probably more of a statistics question than a specific R
question, although I will be using R and need to know how to solve the
problem in R.
I have several sets of data (ejection fraction measurements) taken in
various ways from the same set of (~400) patients (so it is paired data).
For each individual measurement I can make an estimate of the percentage
uncertainty in the
2000 Apr 26
1
Bland Altman plot (was: paste ?)
Dear all,
sorry for this perhaps stupid question, but it concerns my recent
problem as well as the current thread on B-A plot.
I would like to plot something like x+y vs. x-y or mean(x,y) vs
difference (x,y), but my "variables" x,y are actually pairs of
replicates (two observed values of a growth rate by 60 clones). So
the order x,y does not matter and each x,y pair can be arranged
2000 Apr 24
2
paste ?
Dear friends. I've made a very simple procedure to make Bland-Altman plots
and it works OK except for the inability to take a variate as argument in
annotation. I'm sure it is a very simple error, so if you have 5 seconds
please tell me.
Best wishes
Troels
bland <- function (x) #accepts two columns
{
mn <- 0.5*(x[,1]+x[,2])
diff <- x[,1]-x[,2]
2008 Dec 07
2
concordance correlation coefficient using R
Hi.
I have data which i would want to assess the degree of agreement
between two assays, e.g., to evaluate reproducibility or for
inter-rater reliability. I have used the Pearson product-moment
correlation coefficient. It looks good ranginging between 0.90 to
0.998. Though this looks good. I am told the Concordance correlation
coefficient will give a better picture of how reproducible the assay
2011 Jan 18
2
ggplot2, geom_hline and facet_grid
Hi
I have a long data set on which I want to do Bland-Altman style plots for each rhythm type
Using ggplot2, when I use geom_hline with facet_grid I get an extra set of empty panels.
I can't get it to do it with the "Diamonds" data supplied with the package so here is a (much abbreviated) example:
> lvexs
cvd_basestudy ecd_rhythm fixed_time variable_time
1 CBP05J02
2011 Mar 23
2
Estimating correlation in multiple measures data
Dear R-helpers,
This may sound simple to you, but I'm a beginner in this, so please be
forgiving.
I have a following problem: two analytes were measured in patient's
blood on 4 occasions: ProteinA and ProteinB. How to correctly evaluate
correlation between ProteinA and ProteinB?
I tried:
x <- data.frame(Patient.ID=rep(1:10, each=4), Visit=rep(c(1:4),10),
ProteinA=rnorm(m=10,
2001 Jul 10
1
Using R for Data Analysis & Graphics: update
There is now an updated version of
"Using R for Data Analysis & Graphics" on CRAN,
under Documentation | Contributed.
Data sets and scripts are available from my web page,
to which there is a link on the relevant CRAN page.
John Maindonald email: john.maindonald at anu.edu.au
phone : (6125)3473 fax : (6125)5549
Statistical Consulting Unit, Room 1194,
2011 Mar 23
2
Comparing non nested models with correlation coefficients (inspired from Lorch and Myers )
Hi,
I would like to compare two models in R with the same dependant variable but
different predictors (two different types of frequency and reaction times as
RT).
An editor told me to have a look at Lorch and Myers 1990.
Lorch and Myers use the following technique:
1) they perform regressions on individual subjects' data
2) they extract the beta weights
3) they run t-test on these beta
2006 Mar 09
4
IVR woes
Hello all. I'm having a problem debugging an IVR I'm building. I can't see any reason this shouldn't be working.
Firstly the asterisk version is:
Asterisk SVN-trunk-r7230 built by root @ localhost.localdomain on a i686 running Linux on 2006-02-17 22:44:48 UTC
Basically the problem is this. While the playbacks are happening you can push any one of the options and to happily
2011 May 05
6
Averaging uneven measurements by time with uneven numbers of measurements
I have a new device that takes measurements anywhere from every second, to
every 15 minutes (depending on changes). The matrix has a date, time and Y
column (Y is the measurement). For three days it is 25,000 rows. How do I
average the measurements by every 30 minutes so my matrix is 48 rows per
day? I have been working on this and cannot figure out a simple method. Any
ideas? Thank you.
-----
In
2006 Mar 11
2
IVR dial by extension option..
I'm working on an IVR that gives the users the option (number 5 in the main menu) to dial by extension:
exten => 5,1,Set(TIMEOUT(digit)=5) ; Dial Extension
exten => 5,2,Set(TIMEOUT(response)=10)
exten => 5,3,Background(LCL/prompt-60)
exten => 5,4,WaitExten(15)
When going option 5 you can dial some extensions such as 2802, it goes to the extension (all extens start with 28 on the
2005 Apr 15
4
aggregation question
Is length(unique()) what you are looking for?
Andy
> From: Christoph Lehmann
>
> Hi I have a question concerning aggregation
>
> (simple demo code S. below)
>
> I have the data.frame
>
> id meas date
> 1 a 0.637513747 1
> 2 a 0.187710063 2
> 3 a 0.247098459 2
> 4 a 0.306447690 3
> 5 b 0.407573577 2
> 6 b
2007 Sep 11
6
xyplot question
I have the code below and it works fine if I print the xyplot but if I
take the print out, then I just get a blank
pdf. The same holds if I just send the plot to the console without the
print ( I get nothing ). My question is whether this is always
the case with xyplot or is there something wrong with my settings ? I am
on linux ( redhat ) and using R.2.5.0. Thanks.
load("stocks.dat")
2006 Feb 12
1
lme, nlsList, nlsList.selfStart
Dear listers,
I am trying to fit a model using nlsList() using alternately a SSfol()
selfstart function or its developped equivalent formulae.
This preliminary trial works well
mydata<-groupedData(Conc~Tps|Organ,data=mydata)
mymod1<-nls(Conc~SSfol(Dose,Tps,lKe,lKa,lCl),data=mydata)
as well as a developped form:
mymod2<-nls(Conc~Dose * exp(lKe+lKa-lCl) *
2005 Jul 28
1
conversion from SAS
Hi, I wonder if anybody could help me in converting
this easy SAS program into R.
(I'm still trying to do that!)
PROC IMPORT OUT= WORK.CHLA_italian
DATAFILE= "C:\Documents and
Settings\carleal\My
Documents\REBECCA\stat\sas\All&nutrients.xls"
DBMS=EXCEL2000 REPLACE;
GETNAMES=YES;
RUN;
data chla_italian;
set chla_italian;
2011 May 12
1
separate date and time
I have a combined date and time. I would like to separate them out into two
columns so I can do things such as take the mean by time across all dates.
meas<-runif(435)
nTime<-seq(1303975800, 1304757000, 1800)
nDateT<-as.POSIXct(nTime, origin="1970-01-01")
mat1<-cbind(nDateT,meas)
means1<- aggregate(mat1$meas, list(nDateT), mean)
This doesn't do anything as each day