search for: unequal

...p correlated col vectors. Let the row representation be X = (X’_1, . . ., X’_n)’. I generate the differences of these vectors as D_{ab} = X_a – X_b, with different indices a and b, and similarly D_{cd} = X_c – X_d, and make a quadratic form D’_{ab}D_{cd} = A_{abcd}, say. Please note that, here a is unequal b, c is unequal d, a is unequal c, b is unequal d. By slightly shuffling the same set of vectors, I generate two other similar quadratic forms, say A_{acbd} and A_{adcb}, where the indices are again as unequal as stated above. In the R-code (a part of ) below, I compute these three forms using...

Hello, I have some patient data for my masters thesis with three groups (n=16, 19 & 20) I have completed compiling the results of 7 tests, for which one of these tests the variances are unequal. I wish to perform an ANOVA between the three groups but for the one test with unequal variance (<0.001 by both bartlett and levene's test) I am not sure what to do. I thought i would run ANOVA with bonferonni post-test for groups with equal variances, then for the test with unequal varia...

Hello- I have run an ANOVA on 4 treatments with unequal sample sizes (n=9,7,10 and 10). I want to determine where my sig. differences are between treatments using a Bonferroni test, and have run the code: pairwise.t.test(Wk16, Treatment, p.adf="bonf") I receive an error message stating that my arguments are of unequal length: Error in tapp...

I found this paper on ANOVA on unequal error variance. Has this be incorporated to any R package? Is there any textbook that discuss the problem of ANOVA on unequal error variance in general? http://www.jstor.org/stable/2532947?cookieSet=1

Dear Douglas and R-help, Does lme assume normal distribution AND equal variance among groups like anova() does? If it does, is there any method like unequal variance T-test (Welch T) in lme when each group has unequal variance in my data? Thanks, Shirley

Hello, I?ve tried several times to learn R, but have never gotten past a particular gate. My data are organized by column in Excel, with column headers in the first row. The columns are of unequal lengths. I export them as CSV, then import the CSV file into R. I wish to summarize the data by column. R inserts NA for missing values, then refuses to operate on columns with NA. R is importing my data into a data frame, and I realize that is inappropriate for what I want to do. How can I im...

Hello [R]-help I am trying to find > a package where you can do ANOVA based trend analysis on grouped data > using orthogonal polynomial contrasts coefficients, for unequally > spaced factor levels. The closest hit I've had is from this web site: >(http://webcache.googleusercontent.com/search?q=cache:xN4K_KGuYGcJ:www.datavis.ca/sasmac/orpoly.html+Orthogonal+polynomial >l but I cannot find this package or anything like it. [[alternative HTML ver...

...ever, the variance between my groups is not equal and I am not sure if it is therefore appropriate to use a robust statistical method or if a non-parametric analysis (i.e. ranked regression) might be better. If I can still use a robust statistical method, which estimator is best to use to deal with unequal variance? And if it is better to use a non-parametric analysis, could anyone put me in the direction of the right non-parametric method to use (the relationship between my response variable and the covariates is linear)? Any help on this would be greatly appreciated! Many thanks, Geertje ~~~~ Ge...

Hi, I am doing multiple regression, and have several X variables that are categorical. I read that I can use dummy or contrast codes for that, but are there any special rules when there're unequal #observations in each groups (4 females vs 7 males in a "gender" variable)? Also, can R generate these codes for me? THanks.

Hi, How can I read data of unequal number of observations (rows) as is (i.e. without introducing NA for columns of less observations than the maximum. Example: A B C D 1 10 1 12 2 10 3 12 3 10 4 12 4 10 5 10 Thanks in advance. Sachin ------------------------...

...sers, I throw myself on your mercy. Help me, the unworthy, satisfy my employer, the ungrateful. My feeble ramblings follow... I've searched R-Help, the R Website and done a GOOGLE without success for a one way ANOVA procedure to analyse data that are both non-normal in nature and which exhibit unequal variances and unequal sample sizes across the 4 treatment levels. My particular concern is to be able to discrimintate between the 4 different treatments (as per the Tukey HSD in happier times). To be precise, the data exhibit negative skew and platykurtosis and I was unable to obtain a sensible t...

I am using levelplot() from lattice with grids that have unequal cell sizes. This means that the boundary between two cells is not always half-way between nodes, as levelplot() assumes. The result is that some cell sizes are rendered incorrectly, which can be painfully obvious if using relatively large cells. Is there any work-around? I am using the conditio...

Dear R users, I need to merge two data frames based on both equal and unequal comparisons. The "sqldf" package used to work well , but today, I cannot resolve the following error by reinstallation of the sqldf package. Can anyone suggest a different way to perform this kind of merge function? Thank you, Ding > DMRlog2pbde47DMS <- sqldf("select * fr...

Hi, i'm looking for an R function to fit a one-way ANOVA with one factor containing 10 levels. The factor levels have different numbers of observations (varying between 20 to 40). For most of the dependent variables i'm testing there are unequal variances among the factor levels. I see the function oneway.test: oneway.test(variable ~ factor, data=dataset) which by default does not assume equal variances. I also see the basic ANOVA function (aov), which, I think, is OK for unbalanced designs. I get a different F ratio, however, when usin...

Hello, I am hoping someone could shed some light on power calculations for me. I have two small data sets of unequal sample size after NA removal (m = 5, f = 7). m <- c(2.0863, 2.1340, 2.1008, 1.9565, 2.0413, NA, NA) f <- c(1.8938, 1.9709, 1.8613, 2.0836, 1.9485, 2.0630, 1.9143) In a R help message/reply from Sep 30, 2001, it was noted that the "power.t.test" function assumes equal group sizes...

...utput then has length zero as well.) Bill Dunlap TIBCO Software wdunlap tibco.com On Tue, Dec 12, 2017 at 9:41 PM, Maingo via R-help <r-help at r-project.org> wrote: > I'm a newbie for R lang. And I recently came across the "Recycling Rule" > when adding two vectors of unequal length. > > I learned from this tutor [ http://www.r-tutor.com/r- > introduction/vector/vector-arithmetics ] that: > > """""" > > If two vectors are of unequal length, the shorter one will be recycled in > order to match the longer vector. For e...

Has anyone created or rebuilt a Linux Software RAID having mirrored partitions on unequal sized hard disks ? There is a CentOS 5 server having two 400 GB hard disks with five mirrored partitions (software RAID 1) and one of the hard disks is dying. Since new 400 GB HDDs are not available here, we are exploring the possibility of replacing the faulty hard disk with one of a higher capac...

I'm a newbie for R lang. And I recently came across the "Recycling Rule" when adding two vectors of unequal length. I learned from this tutor [ http://www.r-tutor.com/r-introduction/vector/vector-arithmetics ] that: """""" If two vectors are of unequal length, the shorter one will be recycled in order to match the longer vector. For example, the following vectors u and v...

I'am trying to develop some code if R, which would correspond to what I did in SAS. The data look like: Treatment Replicate group1 GSI Control A 1 0.81301 Control B 1 1.06061 Control C 1 1.26350 Control D 1 0.93284 Low A 2 0.79359 Low B

...sible meanings of must alias: 1. A must alias result indicates that the exact same bits in memory are accessed by both.  (This requires both pointer and size to be equal at runtime.) 2. A must alias result indicates that *at least one* bit in memory is accessed by both.  (This allows unequal pointers, and unequal sizes, but not zero sizes.) 3. A must alias result indicates that the two pointers must be equal when accessed at runtime.  (This allows unequal sizes, and zero sizes, but restricts the pointers to be equal.) 4. A must alias result indicates that *at least one* b...