Recent content by gianmarco

  1. gianmarco

    Chi-square test for multiple rows contingency table

    I believe that chi-2 test can be applied. At the end of the day, what you are trying to test is if there is a dependence between rows and columns, i.e. symptoms and disease. In case the test turns out to indicate a significan association, you may want to use standardized residuals to pinpoint...
  2. gianmarco

    calculating similarity between boxplots pair-wisely

    Thank you @hlsmith....I am just trying to replicate something I found in literature.
  3. gianmarco

    calculating similarity between boxplots pair-wisely

    Hello, I was trying to implement a calculation of similarity between data distribution based on box-plots and related five-number summaries. The distance is based on difference between Median, 1Q, 3Q, minimum, and Maximum across variables (see attached picture). My issue is that i have hard...
  4. gianmarco

    Which test should I use?

    Sorry for not coming back to you, I start teaching and my spare time is now very limited. Also, I am scratching my head about how to approach the issue, since your areas are discrete and (at the best of my understanding) there are in-between zones. I was wondering, are there any sites in thos...
  5. gianmarco

    Which test should I use?

    I would agree with that, provided that the areas completely cover the study area, with no gap in-between.
  6. gianmarco

    Which test should I use?

    Hello, I do not know what type of data you have, are you working with some GIS software? Do you have GIS data? For instance, a geometry representing your areas, and a geometry representing your sites? Assuming that you have the above type of data, and assuming that your regions completely cover...
  7. gianmarco

    Importing excel and graphing

    Once you issue that command, a window should pop up allowinfg you to browse through your directories and to choose your file.
  8. gianmarco

    Importing excel and graphing

    Just a small note: for lazy people who do not want to type in the path to the excel file, I would go for something like: mydata <- read_excel(file.choose())
  9. gianmarco

    Dividing each cell value by its column mean

    Thank you Dason. I learned something new today...didnt know the sweep() function. Cheers Gm
  10. gianmarco

    Dividing each cell value by its column mean

    Hello, it should be an easy task but I am experiencing an issue. As per title, I want to divide each cell of the crosstabulation by its column mean. I provide some reproducible example. This is a small dataset: mydata <- structure(list(none = c(4, 4, 25, 18, 10), light = c(2, 3, 10, 24, 6)...
  11. gianmarco

    Chi square effect size - why to use the Crammer's V and not only Phi

    Hello, i do not totally understand your question, but I will try to answer. Phi does not reach its upper ceiling (1) for tables larger than 2x2. In this instance, better to use Cramer's V (which is also called Cramer's phi in some books). Hope this helps Best
  12. gianmarco

    Chi square test

    Hello, i cant remember but there should be an option in SPSS, either something to tick or a button to press (that would lead you to another menu). Apologies if I cant be more specific, but it's a while that i dont use SPSS (which I do not particularly like by the way). Gm
  13. gianmarco

    Chi square test

    Just a supplemetary note: you may want to inspect the (adjusted) standardized residuals to find out which cell significantly contribute to the departure from independence. Best Gm
  14. gianmarco

    Chi squared test assumptions not met

    Hello, the issue is tacked e.g. in Spatz's book (LINK) (pages 316 and following). When saple size (i.e., table's grand total) is large, small expeted frequenciesmight not pose a problem. Also, I think (but not totally sure) that Fisher's exact test might be carried out in your context. What is...
  15. gianmarco

    Long live SAS

    ouch...I wasnt kidding.....