similar to: Code for Coefficent (Cronbach's) Alpha

A short function I wrote for the purpose of evaluating scales made up of a number of questionnaire items. It provides Cronbach's Alpha, both unstandardized and based on standardized items. It also provides item statistics which include item-total correlations (corrected) and item-removed alpha. Thought some of you might find it useful. I would also appreciate any programming tips or

Dear all, I like the way the Rcmdr package computes reliability. E.g reliability(cov(d[,c("q1", "q2", "q3", "q4", "q5", "q6")], use="complete.obs")) will not only give me the alpha score, but also for each variable, alpha.score if deleted. However - when writing scripts it's very tiresome to load the whole Rcmdr GUI just

Dear Listers: I used cronbach{psy} to evaluate the internal consistency and some set of variables gave me alpha=-1.1003, while other, alpha=-0.2; alpha=0.89; and so on. I am interested in knowing how to interpret 1. negative value 2. negative value less than -1. I also want to re-mention my previous question about how to evaluate the consistency of a set of variables and about the total

Sorry, I pasted the wrong file in earlier... this is the correct one: pValCalculator(b, n=20, m=20) { ind <- 1:min(c(n,m)) prob <- (1-pnorm(b,sd=std*sqrt(ind))) prob1 <- sum((n-ind+1)*(m-ind+1)*prob) prob1 } inputData <- scan("/users/lvssso/projects/LAMA/output/pValLamaScore.tmp", list(block1 = "",block2 = "",width1 = 0,width2 = 0,alignment = 0,score

hie 1...i'm trying to carryout a relibility testusing cronbach's alpha what fuctin do i use. 2.. this is more of a statistical question.if the alpha value for all the variables is negative what does it mean. and if the alpha value is negative for all tyha variables but is greater than 0.7 for some sections of the variables what does that mean thanks in advance

Hi list members Any easy way to get standardized cronbach's alpha for a scale, as in SPSS? Thanks Steve Powell proMENTE social research research | evaluation | training & consulting Kranj?evi?eva 35, 71000 Sarajevo mobile: +387 61 215 997 | office: +387 33 556 865 | fax: +387 33 556 866 Checked by AVG Free Edition. 17:44

Dear R members, Is there a way I can include more than one variable in a histogram? Many thanks in advance, Liqing, Liqing Zhang Department of Ecology & Evolutionary Biology 321 Steinhaus Hall U.C. Irvine Irvine, CA 92697-2525 Phone:(949)-824-7703 Fax: (949)-824-2181 Email: lzhang at uci.edu ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Dear All, I am a novice in R and am working on my thesis for master's in Epidemiology & Biostatistics. While calculating Cronbach's alpha for the SF-36 questionnaire, I got all 8 of them more than 1. Is it possible to get alpha more than 1. If yes, please help me understand it. I read about the negative alpha value on your web postings. It does not answer my question though. Thank you.

How would you proceed with the following problem: I have an data frame containing a table relating raw scores on an iq test to 'decile-like' scores. data<-data.frame(age =c( 8, 9, 10, 11, 12, 13, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70), pers90=c(33, 39, 43, 47, 50, 54, 54, 52, 50, 49, 47, 46, 43, 42, 39, 37), perc75=c(27, 31, 37,

Dear all, i need help about comparing 2 alpha cronbach. How to derive W statistic. Are alpha cronbach and Hoyt's method using ANOVA identical? Thank you for your help. Regards --------------------------------- Luggage? GPS? Comic books? [[alternative HTML version deleted]]

A while ago I asked about data management approaches in R. I was asked by several people to post a summary of the responses and alas I am just getting around to doing it. I received several comments, both on and off list. Below is a compilation of these responses. Hope this is as helpful to others as it was to me. Best, Brett 1. Frank Harrell recommended a section, "Operating in

Hello everyone, Can someone point me to some resources on managing data in R and/or S-plus? I have started using R more and more often in my work and I really like it. But, managing data is very different in R and S-Plus than in other packages that I am accustomed to. I know that it is an option to use different workspaces for different projects or to store all objects as source and read them

hi, How can I compute a reliability score of a scale consisting only of dichotomous items? thanks for any help!

List: Thank you for the replies to my post yesterday. Gabor and Phil also gave useful replies on how to improve the function by relying on mapply rather than the explicit for loop. In general, I try and use the family of apply functions rather than the looping constructs such as for, while etc as a matter of practice. However, it seems the mapply function in this case is slower (in terms of CPU

Dear all, I am interested by the various messages sent to the r-help mailing list these last few days about documentation on R. Yet, there are a lot of issues actually open on this topic, and it is not clear to me what is the "urgent need for documentation" on R. R comes with the 'Introduction to R' by Venables et al. I recommend the colleagues and students in my lab who are

Dear Professor Revelle and R-helpers, This is a two-part question: the first part is general, and the second is specific to the psych package. First question: In the past I've constructed composite variables from questionnaire data by using rowMeans(), and then correlating items with the scale using cor() as an informal check for "bad" items. Over the weekend I decided to take a

Dear all, There has been some time since I asked about interpolation in higher (>2) dimensions, and I must admit I failed to write a function to do this myself the last time, but eventually ended up doing it in MATLAB. I tried to translate the MATLAB code, but MATLAB code is so much more opaque than R (S) code, so I failed that too, mainly because I could only get one MATLAB session, I would

Dear all, I'm writing a lgrind definition for R. Lgrind is a program to produce pretty program listings for inclusion in LaTeX documents. Does anybody here have any experience with lgrindefs? My definition now looks like this: R:\ :pb=^\d?\p\d<-\dfunction\(\a\):\ :bb={:be=}:cb=\d#:ce=$sb=":se=\e":lb=':le=\e':id=.:\ :zb=@:ze=@:tb=%%:te=%%:mb=%\$:me=\$%:vb=%\|:ve=\|%:\

Dear all, I'm writing a lgrind definition for R. Lgrind is a program to produce pretty program listings for inclusion in LaTeX documents. Does anybody here have any experience with lgrindefs? My definition now looks like this: R:\ :pb=^\d?\p\d<-\dfunction\(\a\):\ :bb={:be=}:cb=\d#:ce=$sb=":se=\e":lb=':le=\e':id=.:\ :zb=@:ze=@:tb=%%:te=%%:mb=%\$:me=\$%:vb=%\|:ve=\|%:\

Full_Name: Kjetil Kjernsmo Version: 1.0.1 OS: osf1 Submission from: (NULL) (129.240.28.227) Ouch, another obscure bug... I just had a bus error crash, with a core dump, a small one this time. Usual <URL:http://www.astro.uio.no/~kjetikj/tmp/core>. I had done a few simulations, and done a chisq.test() on them. These simulations also write about 190MB's to file, but I have no idea whether