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  1. gianmarco

    Appropriate statistical analysis for 2 groups with 3 possible outcomes

    Hello, I think the Cochran-Armitage test may apply to your situation. See this LINK. Best
  2. gianmarco

    Correspondence analysis - fragment of text

    The basic result of correspondence analysis is a scatter diagram – a perceptual map and set of measures that serves to assess the quality of representation of a multidimensional space on a surface. *I believe you may want to drop the reference to "perceptual map" and stick with scatter diagram...
  3. gianmarco

    Correspondence analysis - fragment of text

    If you are willing to post it here, I would not mind to read it. While I know something about CA, that would allow people more knowledgable than me to jump in a provide further help. cheers. Gm
  4. gianmarco

    Statistical test to assess the relationship between an independent and dependent variable of an experiment

    "to use the one-way ANOVA test to determine whether there is a statistically significant relationship between the density of beech and oak trees and altitude" Put that way, I believe 1-way Anova (or, better, a t-test since you have 2 groups) would test if there is a significant difference in...
  5. gianmarco

    Can you use factor analysis on a table has count data?

    You're welcome. This is a nice, extremely easy to follow, article by M. Bendixen about CA in marketing research: A Practical Guide to the Use of Correspondence Analysis in Marketing Research Attached is the CA scatterplot, made with my CAinterprToolspackage, based on Table 6 of Bendixen's...
  6. gianmarco

    spatial regression with (partly) overlapping areas

    Hello, I believe that other forums (more GIS- or Spatial Analysis-oriented) may provide help. Best
  7. gianmarco

    Can you use factor analysis on a table has count data?

    I have seen in liyerature the use of FA for count data, but (to the best of my understanding) it was before the popularization of CA. CA reduces the number of dimensions useful to represent the table graphically, bringing to the fore latent patterns of association between rows and columns. So...
  8. gianmarco

    Can you use factor analysis on a table has count data?

    Hello, For contingent tables like that, Correspondence Analysis is often used. It has some aspects in common to Factor Analysis, being a method of dimensionality reduction; however, CA is tailored for cross-tabulation and count data. CA is used, for instance, in marketing research to understand...
  9. gianmarco

    Submission of package to CRAN: problem grasping an Error

    @trinker: Thanks for asking. As a matter of fact, eventually I managed to solve the issue and to push the package on CRAN. But I cannot remember how I fixed the error. If I am not mistaken, the problem was with the dataset which the function was using in the example. I recall using a dataset...
  10. gianmarco

    Submission of package to CRAN: problem grasping an Error

    Hello, I have submitted an R package to CRAN; the package is quite small, as it features just one function and three toy datasets. Before submitting to CRAN for evaluation, I have run a check within RStudio (hitting the 'check' button), and fortunately I got no error nor warnings nor notes. I...
  11. gianmarco

    Canonical Correspondence Analysis: how to interpret results

    I am not familiar with CCA, but it has indeed some aspects in common to other dimensionality-reduction techniques which I do know. I will try to give you my two cents on the matter. I think that your interpretation is essentially correct. If a dashed prolongation intersects the vector...
  12. gianmarco

    Function out of my package only works after being copied/pasted...Why?

    Uhmmm....I see.... I will read those documents for sure. What I got from a quick overview is that Imports is "safer" than Depends. Seems ok. But, am I right in understanding that, if I use Imports instead of Depends, I should always indicate within a function of mine to which package a function...
  13. gianmarco

    Function out of my package only works after being copied/pasted...Why?

    Thanks for your comment. Could you please elaborate a little more on "my suggestion to use imports when possible"? What does it mean using imports from a practical standopoint? EDIT: Am I supposed to modify the 'Description' file, and to switch from Depends to Imports?
  14. gianmarco

    Function out of my package only works after being copied/pasted...Why?

    Sorry for not being clear, my bad. I mean that, when you run the function, it does not work. If you copy and paste the whole function into R, and then you re-run the function (will all the need arguments), it works.... Toy dataset # simulate toy data set.seed(12345) monthA_speed <-...
  15. gianmarco

    Function out of my package only works after being copied/pasted...Why?

    Thanks @Dason for replying back. The package (working, if we exclude the windAver() function) is on GitHub. The issue I was describing is with the abovementioned windAver() function: LINK I have tried again, making some modifications (e.g., specifying from which dependency some confusing...
  16. gianmarco

    Function out of my package only works after being copied/pasted...Why?

    Hello, as per title, I am trying to wrap my head around the issue I am experiencing. I am working on a function out of my 'GmAMisc' package; the function is part of a new version which is currently under construction. I am testing the new version, and I have hit 'install/reload', and all is...
  17. gianmarco

    inverting color palete used in a plot in R base

    Hello helicon, thanks for the suggestion. Indeed, I overlooked that....thanks for bringing that to my attention. Cheers Gm
  18. gianmarco

    inverting color palete used in a plot in R base

    Hello, I am trying to invert the color palette used when plotting a RasterLayer. See the attached example that can be reproduced with the code below: require(gdistance) r <- raster(system.file("external/maungawhau.grd", package="gdistance")) plot(r) The output is an image representing the...
  19. gianmarco

    wilcoxon mann whitney or t-test with same results

    Hello, just my 2 cents. First, do not consider MW test as a test of medians. That holds true under specific conditions. Secondly, are you planning to do those tests as a sort of predictors selection? I do not think it would be a sound approach. Best Gm
  20. gianmarco

    Hello, you can contact me at: gianmarco.alberti[at]um.edu.mt Cheers Gm

    Hello, you can contact me at: gianmarco.alberti[at]um.edu.mt Cheers Gm