search for: reproducibilty

Dear Rdevelopers The background for this email is that I was helping a PhD student to improve the speed of her R code. I suggested to replace calls like t(AA)%*% BB by crossprod(AA,BB) since I expected this to be faster. The surprising result to me was that this change actually made her code slower. > ## Examples : > > AA <- matrix(rnorm(3000*1000),3000,1000) > BB <-

Dear list, first apologies for this is not strictly an R question but a theoretical one. I have read that use of k-means clustering assumes sphericity of data distribution. Can anyone explain me what this means? My statistical background is too poor. Is it another kind of distribution, like gaussian or binomial? What does it happen if the distribution is not spherical? Could you give me an

...0.516411 Here is: in $tabulka table like in Minitab output rozptyl = variance smer.odch = standard deviation 5.15 smer.odch = standard deviation * 5.15 proc.rozpt = variance percentage proc.sm.odch = standard deviation percentage Vzorky = Samples Oper = Operators Interakce = Interaction Reprod = Reproducibilty Opak = Repeatability O&R = sum of Reproducibility and Repeatability Suma = Total in $vartab anova table (output from aov call) in $kategorie no of categories which can be estimated safely with method used for analysis in $rozlisitelnost some value from Meloun/Militky book Basically the fun...