similar to: confidence intervals for non-linear regression

Displaying 20 results from an estimated 400 matches similar to: "confidence intervals for non-linear regression"

2010 Mar 03
1
Correct nested design for GLM
Hi, I am currently running the following negative binomial GLM: glm89.nb <- glm.nb(AvGUD ~ Year*Trt*Micro + (0 + Micro/Trt/Year)) where Year has 3 levels, Trt has 2 levels, and Micro has 3 levels. >From what I have read the above model has a 3 way interaction (Year*Trt*Micro), and Micro is nest within Trt and Trt is nested with Year (0 + Micro/Trt/Year). I was hoping someone could
2010 Mar 31
2
lattice: how to add points to the plot generated by levelplot()?
I am using levelplot() function from pkg:lattice and I want to add some points to the plot generated by levelplot() similarly as in basic R graphic sequence: plot(...); points(...), but it does not work. I was reading documentation for lattice, but so far without much success. I would very much appreciate some tips. Best regards, Ryszard
2010 Apr 15
2
predict.lm with NAs
Hi, I wanted to use the predict.lm() function to compare the empirical data with the predicted values. The problem is that I have NAs in my data. I wanted to cbind my data.frame with the empirical values with the vector I get from predict.lm. But they don't have the same length because predict.lm just skip NA-predictions. Is there a way to get a vector with predicted values of the same
2010 Mar 25
1
Expected pairwise.student.t and TukeyHSD behavior?
pairwise.t.test is returning NAs when one of the samples only has one entry, while TukeyHSD returns results (maybe not trustworthy or believable, but results). I stumbled on this because I did not realize one of my samples only had one entry while most of the others had several hundred, so I realize this is not a desirable situation. I'm really just curious about the difference between how
2010 May 11
1
nls() and nls2() behavior?
first, apologies for so many posts yesterday and today. I am wrestling with nls() and nls2(). I have tried to whittle it down to a simple example that still has my problem, yet can be cut-and-pasted into R. here it is: library(nls2) options(digits=12); y= c(0.4334,0.3200,0.5848,0.6214,0.3890,0.5233,0.4753,0.2104,0.3240,0.2827,0.3847,0.5571,0.5432,0.1326,0.3481) x=
2010 Mar 01
3
help with lattice boxplots...
Hi All, I need a small help with following code: I'm trying to convert "dashed lines" to regular ones; and changing default "blue" border color to say "black"... but I'm doing it wrong and its not working. Can anyone help please. Thanks, Code: require(lattice) ex <- data.frame(x=1:10, y=rep(c("A","B"), 5)) bwplot(y~x, data=ex,
2010 Jan 19
1
splitting a factor in an analysis of deviance table (negative binomial model)
Dears useRs, I have 2 factors, (for the sake of explanation - A and B), with 4 levels each. I've already fitted a negative binomial generalized linear model to my data, and now I need to split the factors in two distinct analysis of deviance table:  - A within B1, A within B2, A within B3 and A within B4  - B within A1, B within A2, B within A3 and B within A4 Here is a code that illustrates
2010 Apr 15
2
using nls for gamma distribution (a,b,d)
Dear all i want to estimated the parameter of the gamma density(a,b,d) f(x) = (1/gamma(b)*(a^b)) * ((x-d)^(b-1)) * exp{-(x-d)/a)} for x>d f(x) = Age specific fertility rate x = age when i run this in R by usling nls() gamma.asfr <- formula(asfr ~ (((age-d)^(b-1))/((gamma(b))*(a^b)))* exp(-((age-d)/a))) gamma.asfr1 <- nls(gamma.asfr, data= asfr.aus, start = list(b = 28, a = 1, d= 0.5),
2010 Feb 16
3
Triangular filled contour plot
Hi all, I am working on a filled contour plot which shows a triangular matrix data set (as shown below). Is there a possibilty to draw a triangular filled contour in a equilateral triangle (like a ternary plot)? Thanks in advance Johannes http://n4.nabble.com/file/n1557386/Bild3.png -- View this message in context: http://n4.nabble.com/Triangular-filled-contour-plot-tp1557386p1557386.html
2007 Jan 05
0
outsourcing R work
Dear Colleagues, If you have a need to outsource any coding in R please check the web site of the Research Centre for Cheminformatics in Belgrade, Serbia http://www.rcc.org.yu . We have skilled statisticians experienced in R, fluent in English and with work experience in the West. For more information please check our website http://www.rcc.org.yu/outsourcing.htm or contact me. Kind regards, DK
2010 Apr 23
4
basic table statistics
Hi, I have a very simple question, but I'm obviously not able to solve the problem on my own. I have a data.frame like sample(c("A","B","C"),size=20,replace = T)->type rnorm(20)->value data.frame(ty=type,val=value)->test There must be some built in functions, that will do some descriptive statistics with tabular output, in the end I like to have
2010 Jan 14
3
Barchart bar lengths not proportionate
When I use barchart (with default formatting options), I get bars whose lengths/heights are not proportional to their value. For example: http://drop.io/wbagm6s/asset/capture-png Many of the values in this chart are 1; however, because the blue bars extend to the left of the "0" tick mark, those bars appear to represent higher numeric values. Is there a way to make the length of the
2006 Oct 25
1
Need Help !
Hi I try to install compiz in to my FC5 machine. I have ATI Inc RV280 [Radeon 9200 SE] card. when I try to switch to compiz I get the following error message ============================= compiz --replace gconf compiz: SmcOpenConnection failed: Authentication Rejected, reason : None of the authentication protocols specified are supported and host-based authentication failed libGL warning: 3D
2010 Jan 16
1
Hierarchical Linear Model using lme4's lmer
Hi, I was wondering: I've got a dataset where I've got student 'project's nested within 'school's, and 'division' (elementary, junior, or senior) at the student project level. (Division is at the student level and not nested within schools because some students are registered as juniors & others as seniors within the same school.) So schools are random,
2010 Jan 22
1
confidence intervals for mean (GLM)
Dear useRs, How could I obtain the confidence intervals for the means of my treatments, when my data was fitted to a GLM? I need the CI's for the Poisson and Negative Binomial distributions. Here's what I have: mydata1 <- data.frame('treatments'=gl(4,20), 'value'=rpois(80, 1)) model1 <- glm(value ~ treatments, data=mydata1, family=poisson) means1 <-
2010 Jan 23
2
About LU decomposition in R
Hi, How can I find and download a function in R to do the LU decompostion for finding the upper and lower triangular matrix.  Thank you so much. Joe ___________________________________________________ 您的生活即時通 - 溝通、娛樂、生活、工作一次搞定! [[alternative HTML version deleted]]
2010 Feb 16
2
HELP on Non-Linera Mixed-Effect model
Hi, I'm trying to fit nonlinear mixed effects model using nlme function but getting an error message. Here is what I have: fitted_model = nlme(scores~spline(b1,b2,b3,kt,time), fixed = list(b1~1, b2~1, b3~1, kt~1), random = b1+b2+b3~1, groups= ~id, data = sdat, start = c(b1=3.5,b2=2,b3=.60,kt=3.5),verbose=T) Error: Error in
2010 Jan 04
2
Piecewise regression in lmer
Dear all, I'm attempting to use a piecewise regression to model the trajectory of reproductive traits with age in a longitudinal data set using a mixed model framework. The aim is to find three slopes and two points- the slope from low performance in early age to a point of high performance in middle age, the slope (may be 0) of the plateau from the start of high performance to the
2010 Mar 06
3
scientific (statistical) foundation for Y-RANDOMIZATION in regression analysis
Dear all, I am a statistician doing research in QSAR, building regression models where the dependent variable is a numerical expression of some chemical activity and input variables are chemical descriptors, e.g. molecular weight, number of carbon atoms, etc. I am building regression models and I am confronted with a widely a technique called Y-RANDOMIZATION for which I have difficulties in
2011 Feb 15
1
ternary contour plot
Colin, If your propose is to create a ternary plot with points and vectors, I think easier do this with graphics based plots instead of trellis based plots. Although, with little work you can do with trellis too. I gave you a reproducible code to put an arrow in a ternary plot. I use the function locator() to extract coordinates. The code is the following