similar to: Intercept in model formulae.

Displaying 20 results from an estimated 5000 matches similar to: "Intercept in model formulae."

2010 Mar 04
4
Analogue to SPSS regression commands ENTER and REMOVE in R?
I am not sure if this question has been asked before - but is there a procedure in R (in lm or glm?) that is equivalent to ENTER and REMOVE regression commands in SPSS? Thanks a lot! -- Dimitri Liakhovitski Ninah.com Dimitri.Liakhovitski at ninah.com
2004 Mar 29
2
Confidence Intervals for slopes
Hi, I'm trying to get confidence intervals to slopes from a linear model and I can't figure out how to get at them. As a cut 'n' paste example: ################# # dummy dataset - regression data for 3 treatments, each treatment with different (normal) variance x <- rep(1:10, length=30) y <- 10 - (rep(c(0.2,0.5,0.8), each=10)*x)+c(rnorm(10, sd=0.1), rnorm(10,
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"
2010 Dec 16
1
predict.lm with new regressor names
Hi all, Suppose: y<-rnorm(100) x1<-rnorm(100) lm.yx<-lm(y~x1) To predict from a new data source, one can use: # works as expected dum<-data.frame(x1=rnorm(200)) predict(lm.yx, newdata=dum) Suppose lm.yx has been run and we have the lm object. And we have a dataframe that has columns that don't correspond by name to the original regressors. I very! naively assumed that doing
2009 Mar 07
2
piecewise linear regression
Hi - I'd like to construct and plot the percents by year in a small data set (d) that has values between 1988 and 2007. I'd like to have a breakpoint (buy no discontinuity) at 1996. Is there a better way to do this than in the code below? > d year percent se 1 1988 30.6 0.32 2 1989 31.5 0.31 3 1990 30.9 0.30 4 1991 30.6 0.28 5 1992 29.3 0.25 6 1994 30.3
2012 Mar 01
2
Help with segmented package
Hi everyone. I'm using segmented package to find break point in a bi-linear relationship. In a particular case, I find 1 pointcut (so 2 slopes). I would like to know if it is possible to retrieve information in the segmented object that could let me to plot 1 particular segment with a different color. For example, in that folowing example, I would like to plot the second segment in red.
2010 Jan 17
3
enty-wise closest element
Dear R-users, i have a simple problem maybe, but i don't see the solution. i want to find the entry-wise closest element of an vector compared with another. ind1<-c(1,4,10) ind2<-c(3,5,11) for (i in length(ind2):1) { print(which.min(abs(ind1-ind2[i]))) } for ind2[3] it should be ind1[3] 10, for ind2[2] it should be ind1[2] 4 and for ind2[1] it should be ind1[1] 1. but with the
2007 Nov 28
2
fit linear regression with multiple predictor and constrained intercept
Hi group, I have this type of data x(predictor), y(response), factor (grouping x into many groups, with 6-20 obs/group) I want to fit a linear regression with one common intercept. 'factor' should only modify the slopes, not the intercept. The intercept is expected to be >0. If I use y~ x + factor, I get a different intercept for each factor level, but one slope only if I use y~ x *
2006 Oct 30
1
Random intercept-slope correlation (nlme)
Dear list members, I am working with a multilevel growth curve, that in its simplest form goes like follows: Yit = Ai + Bi t + eit (the error term is assumed to follow an AR(1) autorregressive process) One major topic in my research is the convergence in the values of Y over time. Thus, I am interested in the relationship between the random effects for the intercept and the slope, and I
2011 Mar 31
2
ANCOVA for linear regressions without intercept
Hello R experts I have two linear regressions for sexes (Male, Female, Unknown). All have a good correlation between body length (response variable) and head length (explanatory variable). I know it is not recommended, but for a good practical reason (the purpose of study is to find a single conversion factor from head length to body length), the regressions need to go through the origin (0
2011 Mar 10
2
within group sequential subtraction
Hi Everyone, I would like to do sequential subtractions within a group so that I know the time between separate observations for a group of individuals. My data: data <- structure(list(group = c("IND1", "IND1", "IND2", "IND2", "IND2", "IND3", "IND4", "IND5", "IND6", "IND6"), date_obs =
2009 Sep 11
2
Accumulating results from "for" loop in a list/array
Dear R users, I would like to accumulate objects generated from 'for' loop to a list or array. To illustrate the problem, arbitrary data set and script is shown below, x <- data.frame(a = c(rep("n",3),rep("y",2),rep("n",3),rep("y",2)), b = c(rep("y",2),rep("n",4),rep("y",3),"n"), c =
2011 Mar 09
2
Cleaning date columns
Hi Everyone, I have the following problem: data <- structure(list(prochi = c("IND1", "IND1", "IND1", "IND2", "IND2", "IND2", "IND2", "IND3", "IND4", "IND5"), date_admission = structure(c(6468, 6470, 7063, 9981, 9983, 14186, 14372, 5129, 9767, 11168), class = "Date")), .Names =
2009 Apr 01
3
How to prevent inclusion of intercept in lme with interaction
Dear friends of lme, After so many year with lme, I feel ashamed that I cannot get this to work. Maybe it's a syntax problem, but possibly a lack of understanding. We have growth curves of new dental bone that can well be modeled by a linear growth curve, for two different treatments and several subjects as random parameter. By definition, newbone is zero at t=0, so I tried to force the
2010 May 03
3
how to rewrite this for loops in matrix form without loop
x0=rnorm(100) y0=rpois(100,3)+1 ind=as.data.frame(table(y0)) ind1=ind[,1] ind2=ind[,2] phi=NULL for (i in 1:length(ind2)){ phi[i]=sum(x0[y0==ind1[i]])/ind2[i] } [[alternative HTML version deleted]]
2011 Dec 04
2
frequency table?
Hello R-users, I've got a file with individuals as colums and the clusters where they occur in as rows. And I wanted a table which tells me how many times each individual occurs with another. I don't really know how such a table is called...it is not a frequency table....My eventual goal is to make Venn-diagrams from the occurence of my individuals. So I've this: cluster ind1 ind2
2008 Jun 02
1
Ancova: formula with a common intercept
I have some data with two categorises plus/minus (p53) and a particular time (Time) and the outcome is a continuous vairable (Result). I set up a maximum model. ancova <- lm(Result~Time*p53) > summary(ancova) .. Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 0.05919 0.55646 0.106 0.916 Time -0.02134 0.01785 -1.195 0.241 p53plus
2005 Apr 25
6
Proba( Ut+2=1 / ((Ut+1==1) && (Ut==1))) ?
Dear all, First I apologize if my question is quite simple, but i'm very newbie with R. I have vectors of the form v = c(1,1,-1,-1,-1,1,1,1,1,-1,1) (longer than this one of course). The elements are only +1 or -1. I would like to calculate : - the frequencies of -1 occurences after 2 consecutives -1 - the frequencies of +1 occurences after 2 consecutives +1 It looks probably something like
2011 Dec 04
1
similarity matrix
Hello R-users, I've got a file with individuals as colums and the clusters where they occur in as rows. And I wanted a similarity matrix which tells me how many times each individual occurs with another. My eventual goal is to make Venn-diagrams from the occurence of my individuals. So I've this: cluster ind1 ind2 ind3 etc. 1 0 1 2 2 3 0 1 3
2011 Dec 03
1
pivot table help
Hello R-users, I've got a huge table with about 20.00 rows and 50 columns. The table now has headers as Members1, Members2 etc. My data are 8 different individuals. And I've got a column with clusters. So each individual belongs to different clusters and can occurs multiple times within a cluster (that's the reason that there can be more than 8 members). I want a presence/ absence