Displaying 20 results from an estimated 1000 matches similar to: "Irregular 3d objects with rgl"
2009 Sep 03
2
dividing a dataframe column by different constants
Dear R users, today I've got the following problem.
Here you are a dataframe as example.
There are some SAMPLES for which a CONCentration was recorded through TIME.
The time during which the concentration was recorded is not always the same,
10 points for Sample A, 7 points for Sample B and 11 for sample C
Also the initial concentration was not the same for the three samples.
I would like
2005 Apr 19
3
Help with predict.lm
Hi
I have measured the UV absorbance (abs) of 10 solutions of a substance at
known concentrations (conc) and have used a linear model to plot a
calibration graph with confidence limits. I now want to predict the
concentration of solutions with UV absorbance results given in the new.abs
data.frame, however predict.lm only appears to work for new "conc" variables
not new "abs"
2007 Oct 02
2
plot question
Hello,
I have a question about how to plot a series of data. The folloqing is my
data matrix of n
> n
25p 5p 2.5p 0.5p
16B-E06.g 45379 4383 5123 45
16B-E06.g 45138 4028 6249 52
16B-E06.g 48457 4267 5470 54
16B-E06.g 47740 4676 6769 48
37B-B02.g 42860 6152 19276 72
35B-A02.g 48325 12863 38274 143
35B-A02.g 48410 12806 39013 175
35B-A02.g 48417 9057 40923
2002 Jan 18
2
Replacing data.frame values
Hello,
I have two data frames, NameAndConc.df and
WhichOnes.df. NameAndConc.df has two columns, the
first column is the names of some material, and the
second column is the concentration of active
ingredient.
> NameAndConc.df
name conc
1 material1 0.8
2 material2 0.5
3 material3 0.4
WhichOnes.df has two columns, each of which specifies
which material.
> WhichOnes.df
2012 Mar 27
4
Help on predict.lm
Hello,
I'm new here, but will try to be as specific and complete as possible. I'm
trying to use “lm“ to first estimate parameter values from a set of
calibration measurements, and then later to use those estimates to calculate
another set of values with “predict.lm”.
First I have a calibration dataset of absorbance values measured from
standard solutions with known concentration of
2009 Mar 22
1
Estimating LC50 from a Weibull distribution
I am attempting to estimate LC50 (analogous to LD50, but uses exposure
concentration rather than dose) by fitting a Weibull model; but I
can't seem to get it to work. From what I can gather, I should be
using survreg() from the survival package. The survreg() function
relies on time-to-event data; my data result from 96 h exposures
(i.e., dead or alive after a fixed period; 96 h). I've
2010 Jul 23
2
re-ordering bwplot
Dear list:
I'm using bwplot to compare concentrations by location and treatment as in:
# using built in data
bwplot( conc ~ Type : Treatment, data = CO2 )
I would like the order of the plots to be: 3,4,1,2. I can't seem to figure this out with index.cond or permc.cond.
Any help is appreciated!
Brad Eck
[[alternative HTML version deleted]]
2023 Dec 14
0
R-help Digest, Vol 250, Issue 13
Kevin,
Maybe also look at what air quality monitoring is being done in area.
https://cran.r-project.org/web/packages/RAQSAPI/vignettes/RAQSAPIvignette.html
Depends what and how near, but might be something relevant there?
Karl
Dr Karl Ropkins
Transport Studies | Environment | University of Leeds
------------------------------
Message: 2
Date: Tue, 12 Dec 2023 07:52:59 -0800
From: Bert Gunter
2011 Oct 05
2
gamm: problems with corCAR1()
Dear all,
I?m analyzing this dataset containing biodiversity indices, measured over
time (Week), and at various contaminant concentrations (Treatment). We have
two replicates (Replicate) per treatment.
I?m looking for the effects of time (Week) and contaminant concentration
(Treatment) on diversity indices (e.g. richness).
Initial analysis with GAM models showed temporal autocorrelation of
2012 Nov 18
2
[newbie] convert 3D spatial array to dataframe
summary: how to convert a 3D array (as obtained from ncdf4::ncvar_get)
to a dataframe suitable for use by lattice::levelplot(), e.g.,
levelplot(conc ~ lon * lat | lev, data = data.frame)
details:
I have atmospheric data in netCDF files specifying gas concentrations
over a 3D space with dimensions longitude, latitude, and (vertical)
level. I need to plot the data by level. Since there are
2011 Dec 04
1
Complex multiple t tests in a data frame with several id factors
I have assayed the concentrations of various metal elements in
different anatomic regions of two strains of mice. Now, for each
element, in each region, I want to do a t test to find whether there
is any difference between the two strains.
Here is what I did (using simulated data as an example):
# create the data frame
> elemconc = data.frame(expand.grid(id=1:3, geno=c('exp',
2004 Aug 16
2
using nls to fit a four parameter logistic model
Shalini Raghavan
3M Pharmaceuticals Research
Building 270-03-A-10, 3M Center
St. Paul, MN 55144
E-mail: sraghavan at mmm.com
Tel: 651-736-2575
Fax: 651-733-5096
----- Forwarded by Shalini Raghavan/US-Corporate/3M/US on 08/16/2004 11:25
AM -----
Shalini
2007 Jul 25
4
[LLVMdev] LLVM Expansions
> From: "Wilfred L. Guerin" <wilfredguerin at gmail.com>
> Subject: [LLVMdev] LLVM Expansions
>
> It is very relevant that LLVM look into handeling HDL and other binary
> and analogue operation modeling capbilities, as well as expand this
what is binary? you mean digital right?
> Without confirming the true characteristics of the lower structure
> types and
2005 Jul 19
2
Michaelis-menten equation
Dear R users:
I encountered difficulties in michaelis-menten equation. I found
that when I use right model definiens, I got wrong Km vlaue,
and I got right Km value when i use wrong model definiens.
The value of Vd and Vmax are correct in these two models.
#-----right model definiens--------
PKindex<-data.frame(time=c(0,1,2,4,6,8,10,12,16,20,24),
2004 Jan 20
2
repeated measurements with R
Hello All,
I have a more statistical question, and how this is implemented in R.
The problem is the following:
We have 2 different solutions (samples), which are filtered and then
the concentration of the filtrate is measured.
We want to evaluate how the filter proces and the concentration
measurement influences the detection of the difference of the two
solutions and which step has which
2012 Nov 18
2
[lattice] format and rotation of strip text
Thanks to the lattice gurus on this list, and having reference to the
excellent open-access Sarkar 2008
ISBN 978-0-387-75968-5
e-ISBN 978-0-387-75969-2
http://dx.doi.org/10.1007/978-0-387-75969-2
I now know how to label lattice panels by variable value: see thread
starting @
https://stat.ethz.ch/pipermail/r-help/2012-November/329450.html
(and demonstrated below). This allows me to use
2012 May 03
5
Identifying the particular X or Y in a sorted list
Dear All,
I have a data sets as shown below A (Patient ID ), B and C are the
Concentration of drug in blood on day 1 and day 4, D is the difference in
conc. To do this in R I have written a code as follows, identified the
number of patients who have more concentration on day 4 . Here I want to
identify specifically the patient ID (is he patient 1 or 2 or 5 and 7),
whose concentration is more.
How
2009 Nov 29
1
Plotting observed vs. fitted values
Dear Wiza[R]ds,
I am very grateful to Duncan Murdoch for his assistance with this problem.
His help was invaluable. However, the problem has become a little more
complicated for me. Now, in each plot, I need to plot the observed and
fitted values of a supine and upright posture experiment. Here is what I
have and how far I got.
# tritiated (3H)-Norepinephrine(NE) disappearance from plasma
#
2008 Nov 03
2
standard errors for predict.nls?
Dear all,
Is there a way to retrieve standard errors from nls models? The help page tells me that arguments
such as se.fit are ignored...
Many thanks and best wishes
Christoph
--
Dr. rer.nat. Christoph Scherber
University of Goettingen
DNPW, Agroecology
Waldweg 26
D-37073 Goettingen
Germany
phone +49 (0)551 39 8807
fax +49 (0)551 39 8806
Homepage http://www.gwdg.de/~cscherb1
2005 Oct 11
2
Problems with plot function
Hello all R users,
My simulation function works correctly, but I have problems with plot
function. You will find the following code using it.
Thank you for your help
##################################################"
simulation <- function(k, n){
conc <- seq(0,10,by=0.5)
#choixg <- seq(1, length(conc))
choixg <- rep(0,length(conc))
for (i in 1:length(conc)){
choixg[i]