similar to: mean +/- SEM

Hello, I am beginner in R and I would like to solve the following problem: Suppose that we have three files to be red in R d1, d2, and d3 > d1 id x1 x2 1 1 4 n 2 2 3 h 3 3 0 f > d2 id x1 x2 1 1 2 r 2 2 3 u 3 3 1 f > d3 id x1 x2 1 1 2 a 2 2 1 w Is there any library or function that one can read this datasets like for(i in 1:3) d[i] <-

Hello everybody, I would like to read a SAS Data data1.sas7bdat in R! Is this possible? Thank you a lot in advance ;), Stefo

Hello,   I am using: save(data,file="D:/mayData.RData"), and I have the following error:   Error in save(data, file = "D:/mayData.RData") : error writing to connection   Thank you very much in advance, Stefo [[alternative HTML version deleted]]

Hello all, I read the following variable > x x 1 1_A1_ML1_a.DLL 2 11_B1_ML2_a.DLL 3 4_A1_ML3_a.DLL 4 55_C1_ML4_a.DLL 5 14_C1_ML5_a.DLL I would like to disperse it in three variable such as > x1 [1] 1 11 4 55 14 > x2 [1] "A1" "B1" "A1" "C1" "C1" > x3 [1] "ML1" "ML2" "ML3"

Hi. I am wondering whether Package SEM can do with intercepts and means in its structural analysis. If it can not calculate, how can I make a supplemental function in R? Many thanks in advance. --------========---------- Mitsuo Igarashi mitsu5 at ruby.famille.ne.jp

Dear R Gurus, Sorry if this has been asked before but I did not find it in the archives. I would like to add a horizontal display of mean and SEM on Hmisc ecdf plots done by group (ie variate~treatment). Has anyone written some code to do that ? Thanks and kind regards, Jean-Louis

Dears, I'm a college student and In doing my statistics homework. I use R with SEM package as my tool for sem analysis, but my teacher told me AMOS is more suitable for such analysis. Could someone help tell me whether it is true that some commercial software is better accepted in academic fields? Sorry if I should not post such topics here. -- Best Regards, Reeyarn T. Lee Accounting

Hi, I would like to print elements from sem (structural equation modeling) function (e.g., model-reproduced covariance matrix (C); estimated asymptotic covariance matrix of parameter estimates (cov)). How can I do this? Thanks, Andr?? -- Andr?? Tavares Corr??a Dias Laborat??rio de Ecologia Vegetal Universidade Federal do Rio de Janeiro CCS-IB-Departamento de Ecologia Caixa Postal 68020

Hi experts, I just started to learn R today, and tried to work with an add-on package sem. I have a version of 2.3.1 on MacOS X 10.4.6 with sem put under /Library/Frameworks/R.framework/Versions/2.3/Resources/library However when I typed library(sem) the following error showed up: Error in library(sem) : 'sem' is not a valid package -- installed < 2.0.0? Why is this? Thank

Hello, I use the function sem the following way sem.mod <- sem(model, mod.cov, N=109) where the variables are modelled: Z -> M Z -> I Z -> R M <-> M I <-> I R <-> R Z <-> Z The output is ... Normalized Residuals Min. 1st Qu. Median Mean 3rd Qu. Max. -7.3300 -0.2750 -0.2670 -0.1290 -0.0369 9.0300 Parameter Estimates Estimate Std Error z value Pr(>|z|)

Hello, It has been found that SEM analysis using polychoric correlations + maximum likelihood estimator produces incorrect test statistics and standard errors (e.g., Flora, D. B., & Curran, P. J. (2004). An Empirical Evaluation of Alternative Methods of Estimation for Con?rmatory Factor Analysis With Ordinal Data. Psychological Methods, 9(4), 466-491). Standard errors can be dealt with by

Dear R People: Could someone recommend a "baby book" on path analysis and SEM, please? Or if someone has an example that they use in the classroom setting, that would be very cool too. Thanks in advance, Sincerely, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at gmail.com

Hi, we are trying to do structural equation modelling on R. However, one of our predictor variables is categorical (smoker/nonsmoker). Now, if we want to run the sem() command (from the sem library), we need to specify a covariance matrix (cov). However, Pearson's correlation does not work on the dichotomous variable, so instead we produced a covariance matrix using the Spearman's (or

Sorry if this question has been asked previously, I searched but found little. There also doesn't seem to be a dedicated SEM list-serv so hopefully this will find its way to the appropriate audience. In discussing SEM with a colleague I mentioned that a model they were fitting in AMOS was equivalent to a linear regression and that the coefficients would be the same. This of course was the

Hi there, I just saw your question on the help list and tough you could help me with some start-up info.... I just downloaded the R project software to try running SEM analysis and I also downloaded the SEM package. But it just sits there on the desktop and R does not know where it is...I can¹t figure out how to organize the files...When I type ?sem in R it says object sem not found...I can¹t

I am new to R. I just tried to recreate in R (using sem package and the identical input data) a solution for a simple measurment model I have found before in LISREL. LISREL had no problems and converged in just 3 iterations. In sem, I got no solution, just the warning message: "Could not compute QR decomposition of Hessian. Optimization probably did not converge. in: sem.default(ram =

Hi, I have what is probably a stupid question but I'm confused so here goes: - I have a distribution (n=100) and want to determine if the mean is significantly different from 0.5. - When I plot the 2-tailed 95% confidence limits for the standard error of the mean I find that the upper one just overlaps with 0.5. I was under the impression that this would lead me to conclude that there was

Is it possible to fit a structural equation model with link functions in R? I am trying to build a logistic-regression-like model in sem, because incorporating the dichotomous variables linearly seems inappropriate. Mplus can do something similar by specifying a 'link' parameter, but I would like to be able to do it in R, ofcourse. I have explored the 'sem' package from John Fox,

Is there a "canned" function in R for finding the standard error of the mean? I have tried > sem <- function(x) c(mean =mean(x), + SEM = stdev(x)/sqrt(length(x))) > sem(pnet.lai) Error in sem(pnet.lai) : couldn't find function "stdev" It looks like there is no stdev function in R Thanks, Kirk Kirk R. Wythers email: kwythers at umn.edu University of

hi, I plot path diagrams with the path.diagram() function of the sem package in combination with the graphviz application. Now I want the graphviz code for a path-plot with the actual standardized coefficients on the arrows (not the names). I tried to add edge.labels="values" as an argument to path.diagram() but it's just ignored. can anyone help me on that? p.s.;