search for: rtchiruka

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

how do l programme the logrank test. l am trying to compare 2 survival curves --------------------------------- [[alternative HTML version deleted]]

l'm trying to find the "survdiff" package/function but it seems i cant get it how do l instal it if its not there thanks --------------------------------- [[alternative HTML version deleted]]

hie how do you compute the logrank test using R what commands do you use my data looks something like just an example treatmentgrp strata censoringTime survivalTime censoring act.surv.time [1,] 2 2 42.89005 1847.3358 1 42.89005 [2,] 1 1 74.40379 440.3467 1 74.40379 [3,] 2 2

hie l would like to create about ten strata l have tried using sample(c(1,2),1,replace=TRUE) but all l get is a vector of 1 and 2 if i change it to sample(c(1,10),1,replace=TRUE) it gives me a vector of 1 and 10 how do l go about it --------------------------------- [[alternative HTML version deleted]]

hie i'm tryimg to generate two survival data using the following code (I know its ugly ) but it seems to repeat two of the variables can any one tell me whats the porblem. n=20 n1=n/2 n2=n/4 a11=1 ;a12=1.4 ;a21=16 ;a22=a12 * a21 t1<-array(1,c(n1)) t2<-array(2,c(n1)) treatgrp=matrix(c(t1,t2))

i would like to add a variable to an existing matrix by manipulating 2 previous variables eg for the data m treat strata censti survTime [1,] 1 2 284.684074 690.4961005 [2,] 1 1 172.764515 32.3990335 [3,] 1 1 2393.195400 24.6145279 [4,] 2 1 30.364771 8.0272267 [5,] 1 1 523.182282 554.7659501 l

...; Packages are stored in directories in the file system, so maybe that's > what the author of that line had in mind. > > Duncan Murdoch > > > > ------------------------------ > > Message: 4 > Date: Tue, 1 May 2007 04:25:18 -0700 (PDT) > From: raymond chiruka <rtchiruka@yahoo.com> > Subject: [R] adding column to a matrix > To: r <r-help@stat.math.ethz.ch> > Message-ID: <142954.90575.qm@web33005.mail.mud.yahoo.com> > Content-Type: text/plain > > l have the following dataset and would like to calculate the actual > survival time b...

hie all i am trying to carry out a categorical data analysis but my problem is that when in i use the chi squared test some of my expected values are less than 5. is there a test that can handle this situation. the data is not a 2*2 table. its more from the social sciences where you have from strongly agree to strongly disagree. i know i can collapse vthe tables but there is a loss of

hie when i use plot.survfit to plot more than one graph why I only see the last graph how do i see the other graphs.for example n=20 n1=n/2 n2=n/4 a11=4;a12=4 ;a21=4 ;a22=4 t1<-array(1,c(n1)) t2<-array(2,c(n1)) treatgrp=matrix(c(t1,t2))

I am trying to generate survival data using R .Im trying to randomly generate a column of 1s and 0 and another column randomly generated using an exponential distribution but l cant seem to get the random function. how do l go about it thanks in advance rt chiruka --------------------------------- [[alternative HTML version deleted]]

l want to create a column of 1 and 2 randomly what command should l use eg treatment strata 1 1 2 0 1 1 2 1 2 0 2 1 2 0 1 0 these should be created randomly secondly if l have

l have the following dataset and would like to calculate the actual survival time by if censoring time > survival time then actual survival time =survival time else its= censoring time. treatmentgrp strata censoringTime survivalTime censoring actualsurvivaltim [1,] 1 1 1.012159 1137.80922 0 [2,] 2 2

in R when carring out the log rank test is the censored variable denoted by 1 or 0 or its of no consequence. thanks --------------------------------- always stay connected to friends. [[alternative HTML version deleted]]

hie how do I specify the number of decuimal places for my calulations thanks __________________________________________________ [[alternative HTML version deleted]]

hie carried out a comparison of survival curves using the log rank test in R with the values of rho ranging from -2 to 2 in increments of 0.5 the question is at rho=-1.5 the power of the test seems to fluctuate or differ from the trend shown by the other values of rho is the statistical reason for this difference.ie if the power is increasing as i move from 0 to -2 at rho=-1.5 the power either

l used the following code to generate a sample and then calculated then did a log rank test.can l get the normal version of the logrank eg sqrt of the chisqr(1) will give you the N~(0,1). from my sample can i use the above expression to get the normal dist from the result of the log rank test. thank s=1 while(s!=0){ n=100 m<-matrix(nrow=n,ncol=4)

hie l have obtained a logrank statistic and would like to get the normal version from the same data eg sqrt(chiqsqr)with 1 df ~n(1,0) is this possibe using R or Do l have to programme it thanks --------------------------------- Bored stiff? Loosen up... [[alternative HTML version deleted]]

hie is it possible to get the code for the logrank test l just need the chisquared value. thanks --------------------------------- [[alternative HTML version deleted]]

l would like to create the following matrice treatmentgrp strata 1 1 1 1 1 1 1 2 1 2 1 2 2 1 2 1 2 1 2 2 2 2 2 2 l should be able to choose the size of the treatment grps and stratas the method l used intially creates the