similar to: Cronbach's alpha

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

I am writing to inquire about a warning message that I receive when trying to model a random slope and intercept at the second level of a 3-level model. Specifically, I am testing a 3-level model in which time (WEEK) is nested in participants (PARTICIP) and participants are nested in dyads (DYADID). The goal is to examine how an interpersonal style (CORUMTO) one week predicts changes in

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 All, I'm analysing a negative binomial dataset from a population-based study. Many covariates were determined on household level, so all members of a household have the same value for those covariates. In STATA, there seems to be an option for 'clustered analysis' for neg-bin regression. Does an equivalent exist for R(MASS)'s glm.nb or a comparable function? Many thanks for

Hi, I am trying to run a multilevel model with time nested in people and people nested in dyads (3 levels of nesting) by initially running a series of models to test whether the slope/intercept should be fixed or random. The problem that I am experiencing appears to arise between the random intercept, fixed slope equation AND. (syntax: rint<-lme(BDIAFTER~BDI+WEEK+CORUMTO,

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]]

Hi all-- I am in the process of helping colleagues write up a ms in which we fit zero-inflated Poisson models. I would prefer plotting the rate ratios and 95% CI (as I've found Gelman and others convincing about plotting tables...), but our journals usually like the numbers themselves. Thus, I'm looking at a recent JAMA article in which both numbers and dotplot of RR and 95% CI are

I'm attempting to use xyplot() within a for() loop to plot the relationship between a DV and a series of predictor variables, split by 2 conditioning variables. However, xyplot() does not "seem" to be recognized within the for() loop; I don't receive any error message, but nothing is plotted and a plotting device is not opened. When I use the generic function plot(),

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.

¿existe algún método en el cual no sea necesario hacer este trabajo y que aparezcan los nombres de las preguntas? label.cronbach <- label.var(p01, "¿Le agrada el programa que se le ha mostrado? ") label.cronbach <- label.var(p02, "¿Cree que ayuda en el aprendizaje?") label.cronbach <- label.var(p03, "¿Propicia el trabajo en el equipo?") label.cronbach

Background: Our research group collected data from students via the web about their drinking habits (alcohol) over the last 90 days. As you might guess, some students seem to have lost interest and completed some information but not all. Unfortunately, the survey was programmed to "pre-populate" the fields with zeroes (to make it easier for students to complete). Obviously, when

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

rm(list = ls()) #borra todo lo anterior en memoria setwd("G:/Public/Documents/R/EPICALC/") #como se llama la data desde su path sanda<-read.csv("sandavid2.csv",header=TRUE, sep=",", dec=".") use(sanda) attach (sanda) library (MASS) label.cronbach <- label.var(p01, "¿Consume mucho pan? ") ####¿Hay alguna manera de nombrarlos

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Hi all, I am trying to teach myself to use and program R (How else do you do it? lol) Anyway, I wrote a piece of code to compute coefficent alpha for a scale. As I am neither a statistician nor a programmer, I wanted people's feedback. The code appears to work (Win 95 with R 1.0.1) and I have verified my result with SPSS and it was correct (much to my astonishment!). Nonetheless, I am

Dear r-helpers, I can't get lsa to run because: > library(lsa) Loading required package: Rstem Error in library(pkg, character.only = TRUE, logical = TRUE, lib.loc = lib.loc) : 'Rstem' is not a valid package -- installed < 2.0.0? In addition: Warning message: cannot create HTML package index in: make.packages.html() > install.packages('Rstem') Warning in

Hi, What package would you recommend for analyzing the validity/reliability of multiple choice tests. Doing things such as classical test analysis, factor analysis, item response theory. I've used psychometric (item.exam), MiscPsycho (alpha.Summary), and ltm (rcor.test). MiscPsycho reported the numbers most similar to what I get in SPSS: corrected point biserial correlations,

Hello, Is there a way to compare the relative relevance of fixed and random effects in mixed models? I have in mind measures of effect size in ANOVAs, and would like to obtain similar information with mixed models. Are there information criteria that allow to compare the relevance of each of the effects in a mixed model to the overall fit? Thank you, Bruno

Hi all-- We are planning an intervention study for adolescent alcohol use, and I am planning to use simulations based on a hurdle model (using the hurdle() function in package pscl) for sample size estimation. The simulation code and power code are below -- note that at the moment the "power" code is just returning the coefficients, as something isn't working quite right. The

I'd like to estimate an ordinal logistic regression with a random effect for a grouping variable. I do not find a pre-packaged algorithm for this. I've found methods glmmML (package: glmmML) and lmer (package: lme4) both work fine with dichotomous dependent variables. I'd like a model similar to polr (package: MASS) or lrm (package: Design) that allows random effects. I was