similar to: Updated power.t.test

Hi, I've written some C code for density evaluation of the non-central t distribution. It works with the R-1.7.1 source code if placed in the src/nmath directory and after appropriate changes are made to Makefiles, to the dt function in src/library/base/R/distn.R etc. I haven't read a lot of R source code so it may need some R-ification, but I've tried to use the dt.c file as a

Something like the following should be done for power.t.test to make sure that it doesn't try to evaluate abs(NULL), which results in an error. --- rossini.power.t.test.R 2003-05-30 07:24:49.000000000 -0700 +++ rossini.power.t.test.R.~1~ 2003-05-30 08:47:09.000000000 -0700 @@ -10,7 +10,7 @@ alternative <- match.arg(alternative) tsample <- switch(type, one.sample = 1,

It's the same as PR#2993, fixed yesterday in R-patched & R-devel On Fri, 30 May 2003 rossini@blindglobe.net wrote: > > Something like the following should be done for power.t.test to make > sure that it doesn't try to evaluate abs(NULL), which results in an > error. That's a backwards patch, I presume, or you revert the fix. > --- rossini.power.t.test.R

Hi, I've made a selfStart function for use with gnls and the following piece of code works nicely: check1 <- gnls(y ~ spot.shape.fct(xcord, ycord, background, spotintensity, rho, sigma, delta, mux, muy), start=getInitial(y ~ spot.shape.fct(xcord, ycord, background, spotintensity, rho,

Dear Sir or Madam, What is the formula for power.t.test(delta=delta, sd=segma, sig.level=0.05, power=0.8, type="one.sample", alternative="one.sided")$n? Thank you very much for the help! Best, Xiaorong

Dear all I am trying to calculate the value of n using uniroot. Here is the message I am having: <<< Error in uniroot(integ, lower = 0, upper = 1000, n) : 'interval' must be a vector of length 2 >>> Please would you be able to give me an indication on why I am having this error message. Many thanks EXAMPLE BELOW: ## t = statistics test from t -distribution

curiosity---given that vector operations are so much faster than scalar operations, would it make sense to make uniroot vectorized? if I read the uniroot docs correctly, uniroot() calls an external C routine which seems to be a scalar function. that must be slow. I am thinking a vectorized version would be useful for an example such as of <- function(x,a) ( log(x)+x+a ) uniroot( of, c(

Dear all I am very beginner user of R I want to calculate the power of t-test using power.t.test function. It is stated in the manual that the argument (n) is the number of observations per group. Infact I have a differens number of observations in each group(ie n1<>n2) and another thing is SD the pooled standard deviation of the observations in the two data sets under investigation. Hope

Dear List: The square of the noncentral t-statistic with noncentrality parameter \delta is a noncentral F with noncentrality parameter \lambda=\delta^2. So, t^2_{\nu,\delta} = F_{1,\nu,\lambda=\delta^2}. Consequently, it should follow that t^2_{1-\alpha/2,\nu,\delta} = f_{1-alpha,1,\vu,\lambda=\delta^2}. However, this is not what is happening with the following code. The central

Dear Rusers, I tried to implement a function comparing mean scores between one subject (the patient) and a group a control subjects. The function returns attended results, but I also obtained the following warning : Warning message: the condition has length > 1 and only the first element will be used in: if (substr(fp, 1, 1) == "<") fp else paste("=", fp) Maybe

On 27.06.2017 17:36, Martin Maechler wrote: > This is a continuation of the R-devel thread with subject > "suggestion to fix packageDescription() for Windows users" : > > As I said there, a patch should rather address the underlying > problem in packageDescription rather than a kludgy workaround > patch for citation(). > (For that same reason, Ben Marwick

This is a continuation of the R-devel thread with subject "suggestion to fix packageDescription() for Windows users" : As I said there, a patch should rather address the underlying problem in packageDescription rather than a kludgy workaround patch for citation(). (For that same reason, Ben Marwick proposed to fix packageDescription() rather than the symptom seen in citation().)

Hi Folks, I'm looking for a neat procedure for the following: Given t0 such that pt(t0,df,ncp=0) = alpha (given) find ncp0 such that for given beta pt(t0,df,ncp=ncp0) = (1 - beta) (In other words, what's the ncp such that you get power (1-beta) to detect it, using a 1-sided test with size alpha when ncp = 0?) In the past I've done the groping by hand, but this time it needs

dear R experts---I have been experimenting with the foreach package (with doMC) for a while. my first impression is that it is a very easy way to acquire parallel processing capabilities. (thanks, revolution R.) the only two gotchas were about installation (it required an exit and restart), and the precedence order of the foreach (higher than '+', I think), but once I understood this,

dear R experts--- I am experimenting with multicore processing, so far with pretty disappointing results. Here is my simple example: A <- 100000 randvalues <- abs(rnorm(A)) minfn <- function( x, i ) { log(abs(x))+x^3+i/A+randvalues[i] } ?## an arbitrary function ARGV <- commandArgs(trailingOnly=TRUE) if (ARGV[1] == "do-onecore") { ?library(foreach) ?discard <-

dear R experts---I am looking at a fairly uninformative error in my program: Error in mclapply(1:nrow(opts), solveme) : (converted from warning) all scheduled cores encountered errors in user code the doc on ?mclapply tells me that In addition, each process is running the job inside try(..., silent=TRUE) so if error occur they will be stored as try-error objects in the list. I looked up

Dear all, The help page on the t distribution says: The most used applications are power calculations for t-tests: Let T= (mX - m0) / (S/sqrt(n)) where mX is the `mean' and S the sample standard deviation (`sd') of X_1,X_2,...,X_n which are i.i.d. N(mu,sigma^2). Then T is distributed as non-centrally t with `df'= n-1 degrees of freedom and non-centrality

> On Dec 15, 2014, at 10:13 AM, Simon Urbanek <simon.urbanek at r-project.org> wrote: > >> >> On Dec 15, 2014, at 12:21 PM, Kurt Hornik <Kurt.Hornik at wu.ac.at> wrote: >> >>>>>>> Spencer Graves writes: >> >>> Hello, All: >>> What would it take to make ?iconv? portable? >> >> >>> I

On Dec 15, 2014, at 1:37 PM, Spencer Graves <spencer.graves at prodsyse.com> wrote: > > >> On Dec 15, 2014, at 10:13 AM, Simon Urbanek <simon.urbanek at r-project.org> wrote: >> >>> >>> On Dec 15, 2014, at 12:21 PM, Kurt Hornik <Kurt.Hornik at wu.ac.at> wrote: >>> >>>>>>>> Spencer Graves writes:

R-2.10.1.tar.gz was built a short while ago. This is a maintenance release and fixes a number of mostly minor issues. See the full list of changes below. You can get it from http://cran.r-project.org/src/base/R-2/R-2.10.1.tar.gz or wait for it to be mirrored at a CRAN site nearer to you. Binaries for various platforms will appear in due course. For the R Core Team Peter