search for: phhs80

...that the variances are not equal, and therefore I have tried to apply the classical transformations to have homocedasticity in order to be able to use ANOVA. Unfortunately, no transformation that I have used transforms my data into data with homocedasticity. The histogram of variances is at http://phhs80.googlepages.com/hist1.png Is someone able to suggest to me a transformation to overcome the problem of heterocedasticity? Thanks in advance, Paul

Dear All, Is sqldf equipped with delete queries? I have tried delete queries but with no success. Thanks in advance, Paul

...ce/file") However, if the path to the saved workspace file is a web address, one gets the following error: ?Error in readChar(con, 5L, useBytes = TRUE) : cannot open the connection In addition: Warning message: In readChar(con, 5L, useBytes = TRUE) : cannot open compressed file 'http://phhs80.googlepages.com/workspace20090922', probable reason 'No such file or directory'? To circumvent this problem, one can download the saved workspace file to a local folder with download.file() and the option mode="wb" active. My question is: Should not load() have the same mo...

Dear All, When I am running a program under Wine and I press Control-C, the running program is killed. However, this behavior is not always the desired one. In truth, imagine that the program is doing some calculations that you want to interrupt; if one presses Control-C, the program is killed, but all one wanted was to interrupt the calculations and NOT killing the program. Is there some

Dear All, The following code should return 1, but it returns 0: source("http://r-bc.googlecode.com/svn/trunk/R/bc.R") bc("9 % 2") Do you confirm this bug? Paul

Dear All, Can R produce dot plots like the one of the following picture: http://en.wikipedia.org/wiki/Image:Dotplot_of_random_values.png ? I have tried dotchart, but no success. Thanks in advance, Paul

Dear All I am trying to perform the below optimization problem, but getting (0.5,0.5) as optimal solution, which is wrong; the correct solution should be (1,0) or (0,1). Am I doing something wrong? I am using R 2.5.0 on Fedora Core 6 (Linux). Thanks in advance, Paul ------------------------------------------------------ myfunc <- function(x) { x1 <- x[1] x2 <- x[2] abs(x1-x2) }

Dear All, I am trying to solve the following maximization problem with R: find x(t) (continuous) that maximizes the integral of x(t) with t from 0 to 1, subject to the constraints dx/dt = u, |u| <= 1, x(0) = x(1) = 0. The analytical solution can be obtained easily, but I am trying to understand whether R is able to solve numerically problems like this one. I have tried to find an

Dear All I am doing the following: > x <- yacas("3/2") > for (i in 2:400) + x <- yacas(paste(x,"*",x)) > x expression(Inf^1.260864167e+117/Inf^6.304320836e+116) > Eval(x) [1] NaN No luck this way. However, I am successful with > y <- yacas("(3/2)^400") > y expression(7.05507910865533e+190/2.58224987808691e+120) > Eval(y) [1]

Dear All, Consider the following code: plot(0,0) text(0,0.5,expression(italic(theta))) I would like to get theta in italic, but I always get it upright. Any suggestions? Thanks in advance, Paul

Dear All Can R compute the expected value of a random variable? Thanks in advance, Paul

Dear All, Suppose that you are trying to create a binary logistic model by trying different combinations of predictors. Has R got an automatic way of doing this, i.e., is there some way of automatically generating different tentative models and checking their corresponding AIC value? If so, could you please direct me to an example? Thanks in advance, Paul

Hello everyone, I wanted to ask what will be a good editor to write R scripts in Fedora 7. Tony [[alternative HTML version deleted]]

Dear All I am using Wine 0.9.15 on Fedora Core 5 in connection with WineTools. However, when I create a new database on MS Access (from MS Office2000), I get the following error: "The Dynamic Link Library msjet40.dll could not be located". So, I cannot use MS Access under Wine. Any ideas? Thanks in advance, Paul

Dear All, I am trying to install the package bibliometrix on F28, but getting thsi error: ------------------- ** preparing package for lazy loading Error in dyn.load(file, DLLpath = DLLpath, ...) : unable to load shared object '/usr/lib64/R/library/leaps/libs/leaps.so': libgfortran.so.4: cannot open shared object file: No such file or directory ERROR: lazy loading failed for package

Dear All When drawing a classification tree with plot(mytree) text(mytree) the conditions are written just before the nodes branch. My question is: can one be certain that those conditions refer to the left-side branches? (The R documentation surprisingly lacks the information that I am asking for.) Thanks in advance, Paul

Dear All I am trying to convert from the type "expression" to the type "numeric". The following works: > x <- expression(6.2) > as.numeric(as.character(x)) [1] 6.2 However, the following does not work: > x <- expression(62/100) > as.numeric(as.character(x)) [1] NA Warning message: NAs introduced by coercion Any idea about how to deal with the second case?

Dear All I am trying to install iWidgetsRGtk (on a Linux machine), but getting the following error: > install.packages("iWidgetsRGtk",repos="http://www.math.csi.cuny.edu/pmg") Warning in download.packages(unique(pkgs), destdir = tmpd, available = available, : no package 'iWidgetsRGtk' at the repositories > Any ideas? Thanks in advance, Paul

Dear All, I would like to export, as a pdf file, a plot with the LaTeX font lmodern as the font of my graph. Could somebody please help me? Thanks in advance, Paul

Dear All, According to the Sturges rule, the number of classes of a histogram is the closest integer to 1 + logb(n,base=2) where n is the number of observations. The function hist(), by default, uses the Sturges rule. However, the code x <- 1:200 hist(x) produces a histogram with 10 classes and not 9 classes as determined by the Sturges rule. What am I missing? Thanks in advance, Paul